Efficacy and Safety of CSL222 (Etranacogene Dezaparvovec) Gene Therapy in Adults With Hemophilia B With Pretreatment Adeno-associated Virus Serotype 5 (AAV5) Neutralizing Antibodies (Nabs)
This research study is about a new gene therapy called CSL222 for adults living with Hemophilia B. Hemophilia B is a condition where your blood doesn't clot properly, leading to bleeding problems. The study wants to see how well CSL222 works in people who naturally have certain antibodies (called AAV5 Nabs) in their blood before they even start the treatment. These antibodies might usually stop the gene therapy from working as well. Researchers want to understand if this gene therapy can still safely and effectively reduce bleeding in these specific patients. This is a Phase 3 study, meaning it's one of the final steps before a treatment might become more widely available.
At a glance
What is this study about?
Imagine your body has a special instruction manual for making everything it needs. In people with Hemophilia B, there's a missing or faulty instruction for making a crucial protein called Factor IX (FIX), which helps blood clot. This means they can have frequent and sometimes serious bleeding episodes. Many people with Hemophilia B need regular injections of FIX to prevent these bleeds.
This study is exploring a new type of treatment called gene therapy, specifically CSL222. Gene therapy aims to correct the underlying problem by delivering a working copy of the FIX gene into your body. This allows your own cells to start making FIX, potentially reducing the need for frequent injections and preventing bleeding. The special thing about this study is that it's looking at people who already have certain natural antibodies (called AAV5 Nabs) in their blood. Normally, these antibodies might recognize and attack the 'delivery package' (a harmless virus called AAV5) used to get the new gene into your cells, which could stop the treatment from working.
The main goal of this study is to find out if CSL222 can still safely and effectively reduce episodes of bleeding in adults with Hemophilia B, even if they have these AAV5 Nabs. This is important because if it works, it could mean more people with Hemophilia B might be able to benefit from gene therapy, even those who might have previously been considered unsuitable for it. The study is also looking closely at the safety of this new treatment.
Key takeaways
- This study explores a new gene therapy for adults with Hemophilia B.
- It's specifically for people who have certain natural antibodies (AAV5 Nabs) that might affect gene therapy.
- The aim is to see if the treatment can safely reduce bleeding in these patients.
- Participation involves a single treatment, regular follow-up visits, and an electronic diary.
- Potential benefits include reduced bleeding; potential risks include side effects from the treatment.
- Your decision to join is completely voluntary and you can withdraw at any time.
Who may be eligible?
To be considered for this study, you need to be an adult (age 18 or older) with Hemophilia B. Your Hemophilia B should be moderate to severe, meaning you naturally produce 2% or less of the normal amount of Factor IX (FIX) in your blood. You also need to have been on regular preventative Factor IX treatment for at least two months before the study starts, and have received FIX treatments more than 150 times in your life.
A key part of this study is that you must have a specific type of antibody called AAV5 Nabs present in your blood. These antibodies will be checked twice during the screening process to make sure they are consistently there. You also need to be able to comfortably keep a daily electronic diary during a short lead-in period.
There are also reasons you might not be able to join. These include if you have ever had your body produce 'inhibitors' against Factor IX, which are antibodies that attack the FIX treatment itself. You also can't have certain other medical conditions or abnormal blood test results that suggest liver, kidney, or other significant health problems (like very low blood counts or other bleeding disorders).
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- Are you an adult (18 years or older)?
- Do you have moderate to severe Hemophilia B (Factor IX level 2% or less)?
- Have you been on regular Factor IX preventative treatment for at least 2 months?
- Have you had more than 150 Factor IX treatments in your lifetime?
- Do you know if you have AAV5 antibodies (or would you be willing to be tested and have them)?
- Have you ever had Factor IX inhibitors?
What does participation involve?
Taking part in this study would involve several visits to a study clinic. Before the main treatment, there will be screening visits to check if you're suitable. Once enrolled, you'll receive a single dose of the study treatment, CSL222. After the treatment, you'll have regular follow-up appointments and blood tests to monitor your health and how the treatment is working. This will include checking your Factor IX levels and looking for any side effects. You will also need to continue keeping an electronic diary to track any bleeding episodes or treatments you use. The study will involve a long-term follow-up to understand the lasting effects of the gene therapy, potentially lasting several years. You'll also be asked to follow specific contraception guidelines during the study.
Potential risks and benefits
Locations (26)
- University of California, San Diego (UCSD)Verified postcodeSan Diego, United States· Recruiting
- University of MichiganVerified postcodeAnn Arbor, United States· Recruiting
- Royal Prince Alfred HospitalVerified postcodeCamperdown, Australia· Recruiting
- Royal Brisbane HospitalVerified postcodeHerston, Australia· Recruiting
- Royal Adelaide HospitalVerified postcodeAdelaide, Australia· Recruiting
- The Alfred HospitalVerified postcodeMelbourne, Australia· Recruiting
- McMaster University - HamiltonVerified postcodeHamilton, Canada· Recruiting
- Queen Mary HospitalVerified postcodeHong Kong, Hong Kong· Recruiting
- Prince of Wales Hospital Chinese University of Hong KongVerified postcodeShatin, Hong Kong· Recruiting
- Sheba Medical CenterVerified postcodeTel Litwinsky, Israel· Recruiting
- Centro de Investigacion Clinica GRAMEL S.C.Verified postcodeMexico City, Mexico· Recruiting
- King Faisal Specialist Hospital and Research CenterVerified postcodeRiyadh, Saudi Arabia· Recruiting
Common questions
What is Hemophilia B?
Hemophilia B is a condition where your blood doesn't clot properly because you don't have enough of a protein called Factor IX, leading to more bleeding.
What is gene therapy?
Gene therapy is a treatment that aims to fix the root cause of a disease by adding a working copy of a faulty gene into your body.
What are AAV5 Nabs?
AAV5 Nabs are natural antibodies that some people have, which can recognize and potentially block the gene therapy 'delivery package' (a harmless virus).
Will I still need my usual Factor IX treatment?
The goal is to reduce your need for Factor IX, but your doctors will advise you if and when you can adjust your current treatment plan based on how the gene therapy is working.
How long will I be in the study?
While the active treatment phase might be shorter, there will be a long-term follow-up period to monitor the effects of the gene therapy, potentially lasting several years.
How to find out more
Trial Registration Coordinator
Always speak to your GP or specialist before deciding to take part in a study.
Interested in taking part?
Discussion
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