Frequently Asked Questions

about hemophilia B

What is hemophilia B?

Hemophilia B is a rare bleeding disorder caused by a lack of clotting factor IX in circulation. Insufficient levels of clotting factor can make it difficult or impossible for blood to clot. People with hemophilia B do not bleed harder or faster than a person without hemophilia B—they bleed longer. Approximately 1 in 25,000 males are born with hemophilia B.1

What causes hemophilia B?

Congenital hemophilia B is an inherited disorder that affects mostly males. However, in about 30% of cases, there is no family history of hemophilia B and the condition is likely the result of a spontaneous mutation of a gene.1

Since hemophilia B is in a person's genes, it's a lifelong condition present from birth. The genetic mutation negatively affects the clotting factor, either in quantity or quality.1

How is hemophilia B classified?

Hemophilia B is classified into 3 categories: mild, moderate, and severe. Each category is determined by the specific level of clotting factor IX a person has in circulation.1,2
  • People with mild hemophilia B have >5% to <40% of normal clotting factor in circulation
  • People with moderate hemophilia B have 1% to 5% of normal clotting factor in circulation
  • People with severe hemophilia B have <1% of normal clotting factor in circulation
In addition to bleeding following an injury, people with severe hemophilia B may have frequent spontaneous bleeding episodes, often into their joints and muscles, which can cause long-term damage.1,3

Can hemophilia B affect females?

It is possible for a female to have hemophilia B, although it is considered rare. For the most part, hemophilia B manifests in men, while women typically carry the gene. One way for a female to inherit the condition would be if her father has it and her mother is a carrier. Some female carriers may experience bleeding problems and/or have circulating levels of clotting factor low enough to meet the definition of mild.1

How is hemophilia B treated?

Hemophilia B is treated by increasing the level of factor IX in the blood. To accomplish this, a person with hemophilia B will receive an infusion of clotting factor replacement therapy through the vein.1

There are two primary treatment strategies: infusing prophylactically (prophylaxis) to protect against future bleeds or before surgery, and infusing "on demand" during a bleeding episode to stop the bleeding.4

What are the benefits of prophylaxis?

Prophylaxis is intended to prevent bleeding episodes through regular infusions of clotting factor. The frequency of infusions depends on many things and should be determined by the person with hemophilia and their doctor. On average, however, people with severe hemophilia B usually infuse twice a week in order to achieve protection from bleeds.5 Prophylaxis has been proven to significantly protect people from bleeds.4

What kinds of factor replacement therapies are available?

Plasma-derived clotting factor products are extracted from individuals who donate their plasma. Recombinant clotting factors use DNA technology to reproduce clotting factor proteins in a laboratory without relying on human blood products. Recombinant clotting factors were developed in the 1980s to address the potential for viral contamination of plasma-derived clotting factors, and the first recombinant clotting factor was approved for people with hemophilia B in 1997.6,7

What is an inhibitor and how does it affect treatment?

In some people with hemophilia B, the factor product they use to prevent or treat bleeds may be viewed as foreign by the body's immune system. When the body views factor product as foreign, it reacts against it and develops an antibody—or inhibitor—that may prevent the factor from working, leaving the person unprotected from bleeds. The exact causes of inhibitor formation (genetic and non-genetic) are being actively researched and while inhibitor development is most common during the first year of treatment, it can happen at any time.1

People with hemophilia B who develop an inhibitor require a different approach to treatment than those without an inhibitor. Therapies are more complex and may include the use of bypassing agents such as factor VIII inhibitor bypassing activity (FEIBA) or recombinant factor VIIa (rFVIIa), or an attempt to eliminate the inhibitor through a process called immune tolerance induction (ITI).8

Where can I go to learn more about hemophilia B?

To find a hemophilia treatment center near you, click here.

The following is a list of several organizations focused on hemophilia:

National Hemophilia Foundation
www.hemophilia.org

Hemophilia Federation of America
www.hemophiliafed.org

World Federation of Hemophilia
www.wfh.org

Coalition for Hemophilia B
www.coalitionforhemophiliab.org

References: 1. Roberts HR, Key NS, Escobar MA. Chapter 124. Hemophilia A and Hemophilia B. In: Prchal JT, Kaushansky K, Lichtman MA, Kipps TJ, Seligsohn U, eds. Williams Hematology. 8th ed. New York: McGraw-Hill; 2010. http://www.accessmedicine.com/content.aspx?aID=6117504. Accessed May 11, 2012. 2. White GC, Rosendaal F, Aledort LM, et al; on behalf of the Factor VIII and Factor IX Subcommittee. Definitions in hemophilia: Recommendation of the Scientific Subcommittee on factor VIII and factor IX of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. Thromb Haemost. 2001;85:560. 3. Berntorp E. Joint outcomes in patients with haemophilia: the importance of adherence to preventive regimens. Haemophilia. 2009;15:1219-1227. 4. Tagliaferri A, Franchini M, Coppola A, et al. Effects of secondary prophylaxis started in adolescent and adult haemophiliacs. Haemophilia. 2008;14:945-951.5. Collins PW, Fischer K, Morfini M, et al. Implications of coagulation factor VIII and IX pharmacokinetics in the prophylactic treatment of haemophilia. Haemophilia. 2011;17:2-10. 6. Pipe SW. Recombinant clotting factors. J Thromb Haemost. 2008;99:840-850. 7. US Department of Health and Human Services. Vaccines, Blood & Biologics. http://www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts/licensedproductsblas/fractionatedplasmaproducts/ucm057039.htm. Published February 1997. Accessed May 22, 2012. 8. Astermark J, Santagostino E, Hoots WK. Clinical issues in inhibitors. Haemophilia. 2010;16(5):54-60.

 
         
    

Processing....