Hemophilia B is a genetic bleeding disorder caused by missing or low levels of clotting factor IX. About 1 in 25,000 males are born with it. Treatment has long relied on regular infusions of factor IX concentrate, but gene therapy approved in 2022 now allows some adults to produce their own factor IX after a single treatment.
What's actually going on in research
Trials are testing newer gene therapies with different viral vectors, studying how long gene therapy benefits last, and evaluating extended half-life factor IX products that require less frequent infusions. Researchers are also exploring gene editing approaches and treatments for people with inhibitors — antibodies that make standard factor replacement ineffective.
Gene therapy durability
The FDA-approved gene therapy etranacogene dezaparvovec produces factor IX for years after a single infusion. Trials are now tracking how long this lasts and whether additional doses might be needed.
Gene editing
Instead of adding a working gene, these approaches aim to edit the patient's own DNA to fix the mutation causing hemophilia B. Early trials are testing safety and whether factor IX levels rise.
Inhibitor management
For people who develop antibodies against factor IX, trials are testing bypassing agents and immune tolerance strategies. Emicizumab, which works in hemophilia A, doesn't help hemophilia B, so new options are needed.
What to know before you search
Eligibility often depends on baseline factor IX level, presence of inhibitors, liver health (important for gene therapy), and prior treatments received.
What types of trials are currently open
- Gene therapy trials — Testing one-time treatments that deliver a working factor IX gene. Most involve a single infusion and long-term monitoring of factor IX levels and bleeding rates.
- Gene editing trials — Early studies of treatments that aim to correct the genetic mutation causing hemophilia B, rather than adding a new gene.
- Extended half-life factor trials — Testing modified factor IX products that last longer in the bloodstream, reducing infusion frequency from twice weekly to once every two weeks or longer.
- Inhibitor trials — For people with antibodies against factor IX, trials test new bypassing agents and strategies to make the immune system tolerate factor IX again.
- Surgical outcome studies — Observational research tracking bleeding complications and recovery in people with hemophilia B undergoing surgery.
Recently added Hemophilia B trials
Take an injection of a new gene therapy for bleeding disorders
The purpose of this study is to evaluate the safety, tolerability, immunogenicity , PK, and PD of a single dose of SR604 in participants with Hemophilia A or Hemophilia B, with or without inhibitors （Part A）and to evaluate the safety, PK, PD, and efficacy of multiple doses of SR604 in participants with Hemophilia A or Hemophilia B, or Factor VII (FVII) deficiency, with or without inhibitors (Part B and Part C).
Take a new preventive therapy for hemophilia A or B
The purposes of this open-label, multicenter III clinical trial are to evaluate the safety and efficacy of long-term preventive treatment with KN057 in Haemophilia A or B patients with or without inhibitors, and to assess the pharmacokinetic characteristics of the new and old processes KN057. The participants in Part PK will be randomly assigned to Old process Group or New process Group in a 1:1 ratio. The participants in Old process Group will receive old process KN057 prophylaxis for the first 26 weeks and new process KN057 prophylaxis for the following 26 weeks. The participants in New process Group will receive new process KN057 prophylaxis for both the first 26 weeks and the last 26 weeks. The participants in Part non-PK will be non-randomized and treated with new process KN057 for 52 weeks prophylaxis after enrollment. Priority screening and enrollment of participants who have participated in the KN057-A-301 or KN057-A-302 study.
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