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FIX-GT: Factor IX Gene Therapy Study for Patients with Hemophilia B

About this study

Hemophilia B is an inherited bleeding disorder caused by a defect in the F9 gene. If you have hemophilia B, your liver doesn’t make enough factor IX protein. Factor IX helps your blood clot properly.  It is sometimes known as clotting factor.

Usually, hemophilia B treatment involves frequent doses of factor IX protein, given through your veins. In this clinical trial, we will test a new experimental treatment. We will take a healthy F9 gene and send it to your liver so you can make your own factor IX protein. The healthy gene will be carried by a vector. A vector is a virus that has been disabled so it can no longer cause an infection. This type of intervention is called gene therapy.

FLT180a is the name of the vector used in this study. It is not approved by the U.S. Food and Drug Administration (FDA).

If you qualify for the study, you will come to St. Jude and be given a one-time dose of FLT180a through your veins. You will need to come back to St. Jude or another participating Hemophilia Treatment Center for follow-up visits for six months after receiving the drug.

Eligibility overview

  • Male
  • At least 18 years old
  • Diagnosis of hemophilia B

The above information is intended to provide only a basic description about a research protocol that may be currently active at St. Jude. The details made available here may not be the most up-to-date information on protocols used by St. Jude. To receive full details about a protocol and its status and or use at St. Jude, a physician must contact St. Jude directly.


Full title:

A Phase I/II, Open Label, Multicentre, Ascending Single Dose, Safety Study of a Novel Adeno- Associated Viral Vector (FLT180a) in Patients With Haemophilia B

Study goal:

The main goal of this study is to test the safety of FLT180a at different doses and to find out what effect it has on patients. This is the first time this drug has been used in humans.


Hemophilia B


Males at least 18 years old

Clinical trials categories:

Blood Disorders Hemophilia

For physicians and researchers

Patients accepted to St. Jude must be referred by a physician or other qualified medical professional. Learn how St. Jude can partner with you to care for your patient.


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