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Long-term Safety Study of Etranacogene Dezaparvovec in Adult Men with Hemophilia B

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the long-term safety and effectiveness of a treatment for Hemophilia B, a genetic disorder that affects the blood's ability to clot properly. The treatment being studied is called Etranacogene Dezaparvovec, also known by its code name CSL222. This treatment is a type of gene therapy, which involves using a specially designed virus to deliver a healthy version of a gene to the liver, where it can help produce a protein called Factor IX that is essential for blood clotting.

The purpose of this study is to monitor adult male participants who have previously received the CSL222 treatment in earlier studies. Participants will be followed over a long period to observe any potential side effects and to assess how well the treatment continues to work in reducing bleeding episodes. The study will also look at the participants' quality of life and their need for additional treatments to manage their condition.

Throughout the study, participants will have regular check-ups to track their health and any changes in their condition. The study aims to provide valuable information on the long-term benefits and safety of Etranacogene Dezaparvovec for individuals with Hemophilia B, helping to improve future treatment options for this condition.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Participation begins after completing a previous study with etranacogene dezaparvovec or after at least 5 years since receiving the treatment.

    Written consent is required to confirm understanding and agreement to follow the study requirements.

  2. Step 2

    Treatment administration

    The treatment involves an IV infusion of Hemgenix, which is a solution containing etranacogene dezaparvovec.

    This step is completed prior to the start of this long-term follow-up study.

  3. Step 3

    Monitoring and follow-up

    Regular assessments are conducted to monitor for any serious adverse events or specific health concerns.

    The study evaluates the long-term safety and effectiveness of the treatment.

  4. Step 4

    Evaluation of bleeding episodes

    The frequency of bleeding episodes is recorded, including spontaneous, joint, and traumatic bleeding.

    The goal is to observe any reduction in bleeding episodes over time.

  5. Step 5

    Factor IX activity assessment

    The activity level of Factor IX in the blood is measured to determine the treatment's effectiveness.

    Changes from the baseline level are tracked during each visit.

  6. Step 6

    Quality of life evaluation

    Quality of life is assessed using specific questionnaires designed for individuals with hemophilia.

    Changes in quality of life scores are analyzed to understand the impact of the treatment.

  7. Step 7

    Study completion

    The study is expected to continue until March 23, 2035.

    Participants will be monitored throughout the study duration to gather comprehensive data on long-term outcomes.

Who can join the trial?

6 criteria

  • The patient must be an adult male.
  • The patient must have **Hemophilia B**, which is a condition where the blood doesn't clot properly.
  • The patient must have received treatment with a medication called **CSL222** in either Study CSL222_2001 or Study CSL222_3001.
  • The patient must have completed participation in Study CSL222_2001 or Study CSL222_3001, or at least 5 years must have passed since receiving CSL222.
  • The patient must have provided written informed consent, which means they have agreed in writing to participate in the study after being informed about it.
  • The patient must be willing and able to follow all the study requirements.

Who cannot join the trial?

4 criteria

  • Only adult males can participate, so females cannot join the study.
  • Participants must have been treated with a specific treatment called CSL222 in previous studies named CSL222_2001 or CSL222_3001. If you haven't been part of these studies, you cannot participate.
  • The study is for those with a condition called Hemophilia B, a genetic disorder that affects blood clotting. If you do not have this condition, you cannot join.
  • The study does not include vulnerable populations, which means people who might need special protection or care are not eligible.
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Investigated drugs

Etranacogene Dezaparvovec (CSL222) is a gene therapy being studied for its long-term safety and effectiveness in adult males with Hemophilia B. This therapy aims to provide a potential treatment by delivering a functional copy of the gene responsible for producing a clotting factor that is deficient in individuals with Hemophilia B. The goal is to reduce bleeding episodes and improve the quality of life for patients.

What is already known about the treatment

Etranacogene Dezaparvovec – This medication is administered as a single intravenous infusion. It is currently being studied in clinical trials for its long-term safety and effectiveness in treating Hemophilia B. The main therapeutic indication is for adult males with Hemophilia B, a genetic disorder that affects blood clotting. Etranacogene Dezaparvovec works by delivering a functional copy of the gene responsible for producing factor IX, a protein crucial for blood clotting, directly into the patient's liver cells. It is classified as a gene therapy product, aiming to provide a long-term solution by addressing the underlying genetic cause of the disorder.

Investigated diseases

Hemophilia B – Hemophilia B is a genetic disorder where the blood does not clot properly due to a deficiency of a protein called Factor IX. This condition leads to prolonged bleeding after injuries, surgeries, or even spontaneously without any apparent cause. Individuals with Hemophilia B may experience frequent nosebleeds, easy bruising, and bleeding into joints and muscles, which can cause pain and swelling. Over time, repeated bleeding into joints can lead to joint damage and arthritis. The severity of symptoms can vary, with some individuals experiencing mild symptoms and others having more severe bleeding episodes. Hemophilia B is typically inherited, affecting mostly males, as it is linked to the X chromosome.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2023-503765-37-00Protocol codeCSL222_3003Estimated enrolment56 patientsSponsorCSL Behring LLC

sourced from the EU Clinical Trials Register and site verification

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