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Recovery Act Investments in Hemophilia

Public Health Burden

Hemophilia is a rare, usually inherited, bleeding disorder in which blood does not clot normally. Those affected can experience prolonged bleeding into soft tissues and joints even after unnoticed injury and internal bleeding that may be life-threatening. Hemophilia affects approximately 18,000 people (almost exclusively males) in the United States; nearly 400 babies are born with the disorder each year. Patients with hemophilia A, which occurs in 4 out of 5 people with hemophilia, have missing or low levels of a protein called clotting factor VIII. Patients with hemophilia B have missing or low levels of clotting factor IX.


The standard treatment for hemophilia is intravenous administration of either clotting factor VIII for hemophilia A or clotting factor IX for hemophilia B. Unfortunately, up to 30% of individuals with severe or moderately severe hemophilia A develop inhibitors (antibodies) that make infused clotting factor less effective or ineffective. Recovery Act-funded grantees are:

  • Exploring why African American hemophilia A patients make factor VIII inhibitors twice as frequently as Caucasian hemophilia A patients. The results of the study may lead to development of a factor VIII product that is better matched to African American patients.1
  • Testing an oral drug treatment, ataluren (PTC 124ฎ), in patients with hemophilia A and B to increase clotting factor production in individuals who have a gene defect that results in clotting proteins that are shorter than normal and do not work correctly.2

Basic Research

Basic research is needed to develop improved approaches to treat hemophilia A and B by gene therapy (delivery of normal factor VIII and factor IX genes by specially engineered viruses to animals and humans) and to reduce the adverse effects of clotting factor inhibitors on treatment. NIH Recovery Act funds support basic investigations including:

  • Investigating the effects of inhibitors to factor VIII in mice with hemophilia A to aid in the identification of parts of the inhibitory antibodies that are recognized by the immune systems of humans with hemophilia A.3
  • Improving the efficiency of gene delivery in mice, developing methods to prevent and control immune responses to genetically delivered factor VIII in hemophilia A mice, and correcting hemophilia A in mice and dogs without having to use viruses to deliver the factor VIII gene.4
  • Improving gene delivery of factor IX to the livers of mice, rats, and dogs with hemophilia B by using ultrasound and microbubble techniques.5
  • Studying activated factor IX to identify the areas of the protein that regulate its activity. 6
  • Studying the movement of clotting factor VIII within cells through a transport receptor and determining the effects of a missing receptor on producing low clotting factor blood levels.7

  1. 1. 1 RC2 HL101851-01 – Mechanisms of Race-Based Differences in Factor VIII Immunogenicity in Hemophilia – Howard, Tom Eugene—(CA)
  2. 2. 1 RC1 HL100159-01 – Phase 2A Study of Ataluren in Hemophilia A and B (IND104,321) – Miller, Langdon LeForrest – (NJ)
  3. 3. 2 R01 HL082609-05 – The Immune Response to Factor VIII– Lollar, John B. – (GA)
  4. 4. 2 R01 HL069049-06A1 – Nonviral Gene Medicine for Hemophilia A – Miao, Carol – (WA)
  5. 5. 3 R21 HL089038-01A1S1 – Ultrasound-Mediated Gene Therapy for Hemophilia B – Miao, Carol – (WA)
  6. 6. 3 R01 HL075696-05S2 – Structural Mechanisms of Factor IXA Function – Neuenschwander, Pierre Fernand – (TX)
  7. 7. 3 R01 HL094505-01S2 – ER-to-Golgi Transport of Coagulation Factors V and VIII – Zhang, Bin – (OH)

Last Updated April 26, 2010

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