Hemophilia B is an inherited bleeding disorder caused by deficiency or dysfunction of clotting factor IX, leading to prolonged and potentially life-threatening bleeding after injury or surgery, and spontaneous bleeding into joints and muscles in severe cases. It is caused by mutations in the F9 gene on the X chromosome and affects predominantly males. Regular prophylactic factor infusions have greatly improved quality of life but require frequent intravenous access.
What's actually going on in research
Extended half-life factor IX products have reduced infusion frequency for prophylaxis to once weekly or even less often in some patients. Fitusiran, an antithrombin-targeting RNA interference therapy, and concizumab, a monoclonal antibody, offer non-factor subcutaneous prophylaxis options for people with or without inhibitors. Most transformatively, gene therapy using AAV-based delivery has achieved long-term factor IX expression in clinical trials: etranacogene dezaparvovec is now approved and demonstrated sustained high-level factor IX activity after a single infusion.
Gene therapy approval
Etranacogene dezaparvovec is now approved for severe hemophilia B and has demonstrated durable factor IX expression over years after a single infusion, offering potential freedom from ongoing prophylaxis.
Non-factor subcutaneous prophylaxis
Fitusiran and concizumab offer subcutaneous injection prophylaxis that does not require factor replacement, benefiting patients — including those with inhibitors — who find intravenous access difficult.
Inhibitor treatment
Emicizumab, approved for hemophilia A with inhibitors, and new agents are being studied in hemophilia B patients who develop inhibitors against factor IX replacement therapy.
What to know before you search
Eligibility depends on factor IX activity level, inhibitor status, prior treatment history, and liver health for gene therapy trials.
What types of trials are currently open
- Gene therapy trials — Follow-up and new-generation AAV gene therapy programs for hemophilia B with improved vectors and expression.
- Non-factor prophylaxis trials — Testing fitusiran, concizumab, and related agents for bleeding prevention without factor IX infusions.
- Extended half-life factor trials — Evaluating next-generation long-acting factor IX products for reduced-frequency prophylaxis.
- Inhibitor management trials — Studying immune tolerance induction and bypass agents for hemophilia B patients with inhibitors.
- Quality-of-life and joint health studies — Assessing joint outcomes and daily functioning in patients switching from standard to novel prophylaxis.
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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