RecruitingPhase 3NCT06003387
Blood
Hemophilia B
Also known as Factor IX deficiency, Christmas disease, F9 deficiency
Hemophilia B is caused by deficiency of clotting factor IX, resulting in a bleeding phenotype similar to but distinct from hemophilia A. Fitusiran (Alhemo), a subcutaneous antithrombin inhibitor, works for both hemophilia types without need
ORPHA:98879 ↗Gene F9Prevalence 1-9 per 100,000 (Orphanet)Onset Neonatal, Infancy, ChildhoodGenetic (X-linked recessive)
29
studies recruiting now
as of 7 Sept 2026
349
studies registered in total
as of 7 Sept 2026
30
countries with a recruiting site
as of 7 Sept 2026
16 Dec 2025
most recent study posted
among recruiting studies
Recruiting trials
RecruitingPhase 3NCT04563520
SAFE Study: Safety of aPCC Following Emicizumab Prophylaxis
RecruitingNCT04398628
ATHN Transcends: A Natural History Study of Non-Neoplastic Hematologic Disorders
RecruitingPhase 3NCT07285460
A Study to Investigate the Efficacy and Safety of Fitusiran Prophylaxis in Male Participants Aged 1 to Less Than 12 Years With Hemophilia A or B
RecruitingPhase 3NCT05611801
A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
Showing the 5 most recently updated recruiting studies, as recorded 7 Sept 2026. Live status on each study page.
See all 29 recruiting studiesWhere recruiting studies are running
Countries with at least one recruiting site among the studies above, 7 Sept 2026. Tap a country to search trials there.
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About Hemophilia B
Hemophilia B is caused by deficiency of clotting factor IX, resulting in a bleeding phenotype similar to but distinct from hemophilia A. Fitusiran (Alhemo), a subcutaneous antithrombin inhibitor, works for both hemophilia types without needing factor replacement. Gene therapy (etranacogene dezaparvovec / Hemgenix) received FDA approval in 2022 and provides sustained factor IX levels for years from a single infusion.
Common clinical features
Reduced factor IX activityJoint hemorrhageProlonged bleeding after dental extractionIntramuscular hematomaDelayed onset bleedingIntracranial hemorrhageProlonged bleeding timeCephalohematoma
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Treatments being studied
13 approved treatments and 9 in clinical development, from Open Targets (CC BY 4.0). Not medical advice.
Approved: Coagulation Factor Ix Human (Coagulation factor ix human component of balfaxar)Approved: Characterised Viable Autologous Cartilage Cells Expanded Ex Vivo Expressing Specific Marker Proteins (Chondrocelect)Approved: Albutrepenonacog Alfa (Idelvion)Approved: Nonacog Beta Pegol (Refixia)Approved: Etranacogene Dezaparvovec (Hemgenix)Approved: Coagulation Factor Ix Recombinant Human (Benefix)Approved: Eptacog Beta (Activated) (Cevenfacta)Approved: Concizumab (Alhemo)Approved: Spheroids Of Human Autologous Matrix-Associated Chondrocytes (Spherox)Approved: Eftrenonacog Alfa (Alprolix)Approved: Eptacog Alfa (Activated) (Novoseven)Approved: Fidanacogene Elaparvovec (Beqvez)Approved: Marstacimab (Hympavzi)
Phase 3Anti-Inhibitor Coagulant Complex
Phase 3Trenonacog Alfa (Ixinity[tm])
Phase 3Vatreptacog Alfa (Activated)
Phase 3Fitusiran
Phase 2Bay-1093884
Phase 2Eptacog Alfa Pegol (Activated)
Phase 2Ataluren (Translarna)
Phase 1/2Verbrinacogene Setparvovec
+ 1 more in development
Before you apply
Things trial teams commonly ask about for Hemophilia B. Not eligibility rules; those are set by each study.
- Severity class and baseline factor IX activity level (IU/dL) are required for trial enrollment
- Gene therapy trials typically require no inhibitors and no prior AAV5 gene therapy
- Hepatitis history and liver health are screened carefully in gene therapy eligibility
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).