About this study
Hemophilia B is a disease where the blood does not clot well because the body does not make enough of a protein called Factor IX (9). Right now, boys with this disease need regular medicine to help their blood clot. But taking this medicine can be hard, especially for teens. Some stop taking it regularly, which can lead to more bleeding and joint problems. This study is trying to find a new way to help.
The study tests a gene therapy called CSL222. This treatment uses a virus that does not cause illness to carry a special gene into the liver. The gene tells the body to make more Factor IX. Before the study, patients will be watched for at least 6 months while they keep taking their regular medicine. Then they will get one dose of CSL222 through an IV. After the treatment, doctors will check on them for 5 years to see how well it works and if it is safe.
Doctors will do many tests to check each patient’s health. These include blood tests, liver scans, x-rays, and bone scans. The study will also look at how the patients grow and go through puberty. Patients will answer questions about their health and how they feel.
Doctors will watch each patient closely and treat any health issues that come up.
We hope this study will help people with hemophilia B live better lives. If the treatment works, patients may bleed less and not need regular medicine. This could help them be more active, feel better, and worry less about bleeding. The study may also help doctors learn more about gene therapy so they can help more people in the future.
Eligibility overview
- Assigned male at birth
- 12–17 years old
- Severe or moderately severe hemophilia B with factor level less than 2%
- Has been on regular Factor IX for at least 2 months