Treatment of Hemophilia B
Health ConditionsBlood DisordersHemophilia

Treatment of Hemophilia B

Treatment of Hemophilia B
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Updated on December 11, 2025
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Hemophilia B, also known as Christmas disease, is a rare genetic bleeding disorder caused by low levels of the blood protein called factor 9. Factor 9 is a specialized protein necessary for blood clotting.

 In contrast, the lack or insufficiency of clotting factor 8 causes hemophilia A.

 It is three to four times more common than hemophilia B.

Without enough of the clotting factor, people with hemophilia bleed longer than those without the disease. Their bodies are unable to effectively stop the flow of blood from wounds. Hemophilia B is considered mild, moderate, or severe depending on the level of factor 9 present and, relatedly, how easily bleeding occurs. People with mild hemophilia B typically experience bruising and bleeding only after injuries, trauma, surgery, and dental procedures.

People with moderate or severe hemophilia B may experience bleeding after minor injuries or even spontaneously, for no apparent reason. Spontaneous bleeding may occur internally into the joints and muscles as well as into the kidneys, stomach, intestines, and brain, among other organs.

 Left untreated, hemophilia B may result in long-term joint problems and brain hemorrhage.

 There is no cure for hemophilia B, but adequate treatment can stop bleeding episodes. Most people who have hemophilia B are able to lead a fairly normal life.

Treatment to Increase Clotting Enzymes

Hympavzi, a drug that was approved by the U.S. Food and Drug Administration (FDA) in October 2024, has been shown to prevent or reduce the number of bleeding episodes by increasing clotting enzyme production. It lowers the amount of anticoagulation proteins in the body, called tissue factor pathway inhibitors.

 When the level of these proteins is reduced, the body is able to produce more thrombin, the enzyme that causes blood clotting to happen.
Anyone ages 12 and older who has hemophilia A without factor 8 inhibitors, or hemophilia B without factor 9 inhibitors (neutralizing antibodies), can use this medicine for treatment. The drug is dispensed weekly through a prefilled auto-injection pen.

In March 2025, the FDA approved another new medication, Qfitlia (fitusiran). This drug is the first antithrombin-lowering (AT) therapy for routine use to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients 12 and older who have hemophilia A or hemophilia B, with or without factor 8 or 9 inhibitors (neutralizing antibodies).

Qfitlia works by reducing the amount of a protein called antithrombin, leading to an increase in thrombin — an enzyme critical for blood clotting. Qfitlia is injected just below the skin using a prefilled pen, and it can be given once every two months.

Factor 9 Replacement Therapy

Standard treatment for hemophilia B involves replacing the missing clotting factor so that the blood can clot properly. This is called factor 9 replacement therapy. Healthcare providers infuse the two main replacement therapies — plasma-derived factor concentrates and recombinant factor concentrates — into the bloodstream via a vein in the arm.

In both cases, patients receive infusions of the concentrates prophylactically, meaning they receive them regularly to prevent bleeding episodes.

 But if you have severe hemophilia B, you may also need to take a factor 9 concentrate before surgery or dental work.

People who have hemophilia usually learn to self-administer their replacement therapy at home. In fact the National Bleeding Disorders Foundation (NBDF) has self-infusion instructions for kids who are mature enough to learn how to infuse their own factor.

 The cost of factor 9 replacement therapy is significant. The average annual cost of clotting factor therapies for a person with severe hemophilia is roughly $300,000, and overall yearly medical expenses can be twice that.

Plasma-Derived Factor 9 Concentrates

Manufacturers derive plasma-derived factor 9 concentrates from human donations of blood or plasma.

The liquid part of blood, called plasma, contains clotting factors and other proteins, such as antibodies and albumin.

 Albumin is a protein made by your liver to help keep fluid from leaking out of your blood vessels.

All donated blood or plasma undergoes testing for viruses. The plasma goes through multiple processes to separate it into components, such as clotting factors. The clotting factors are freeze-dried and treated to kill (or make inactive) any viruses found.

Two plasma-derived factor 9 concentrates are available in the United States:

  • AlphaNine SD contains only blood factor 9 and no other factors.

Profilnine contains factor 9 along with factor 2, factor 10, and low levels of factor 7.

Recombinant Factor 9 Concentrates

About three-fourths of people with hemophilia take recombinant factor 9 concentrates.

These products are developed in the lab using DNA technology. Recombinant factor 9 concentrates are not able to spread bloodborne viruses, because they are synthetic and not from humans.

Available recombinant factor 9 concentrates include:

  • Alprolix
  • Benefix
  • Idelvion, which also contains albumin

  • Ixinity
  • Rebinyn
  • Rixubis
The Medical and Scientific Advisory Council (MASAC) of the NBDF recommends recombinant factor 9 concentrates over plasma-derived concentrates because they are safer.

Inhibitors: A Serious Treatment Complication

About 3 in 100 people with hemophilia B develop an inhibitor — a type of antibody — to their treatment product. When this happens, the body stops accepting the factor concentrate as a normal part of itself, triggering antibodies to destroy the foreign substances.

 Doctors advise people with hemophilia to get tested for inhibitors yearly so they can prevent serious health problems. Inhibitors don’t necessarily cause symptoms, so a laboratory test is the only way to know whether a person has one.
Treatment for an inhibitor is complex and requires specialized medical expertise. It’s also costly: A person with an inhibitor usually has medical expenses of more than $1 million per year.

Other Medications Used in Hemophilia B Treatment

In certain situations, drugs known as antifibrinolytics are used in addition to factor 9 replacement to assist with blood clotting and reduce blood loss.

Aminocaproic acid (Amicar) is a medication that prevents blood clots from breaking down. It is often used for bleeding in the mouth or after a tooth has been removed, because it blocks a substance found in the saliva that breaks down clots. It may also be recommended before dental procedures.

The drug can be taken orally as a pill or a liquid or can be infused through a vein. The MASAC notes in its treatment recommendations for hemophilia and other bleeding disorders that a dose of factor concentrate must be given first to form the clot, followed by aminocaproic acid to preserve the clot.

Tranexamic acid (Lysteda) similarly slows the breakdown of blood clots. It’s typically prescribed to treat heavy menstrual bleeding in girls and women ages 12 and older to reduce menstrual blood loss.

Hemophilia Treatment Centers

The Centers for Disease Control and Prevention (CDC) recommends that people with hemophilia B who are undergoing factor 9 replacement therapy do so with the help of a hemophilia treatment center (HTC). These are specialized care centers that provide patients with care and education to address all complications related to hemophilia.

The medical staff at HTCs typically includes:

  • Physicians, in particular hematologists (blood specialists)
  • Lab medical technologists
  • Pathologists (body tissue and fluids specialists)
  • Orthopedists (bone, joint, and muscle specialists)
  • Nurses
  • Social workers and other mental health professionals, such as psychologists
  • Physical therapists
  • Other healthcare providers specialized in the care of people with bleeding disorders
Research from the CDC shows that people who used an HTC for their care were 40 percent less likely to die of a hemophilia-related complication than those who didn’t go to an HTC. And those patients who used an HTC were also 40 percent less likely to be hospitalized for bleeding complications than those who didn’t.

The CDC has a directory to help you find an HTC near you.

Gene Therapy for Hemophilia B

Gene therapy eliminates the need for repeated treatment. With gene therapy, a one-time infusion gives the body a working copy of the faulty gene that causes hemophilia. This working gene provides instructions for the body to produce the missing clotting factor.

In November 2022, the FDA approved the first gene therapy for hemophilia B: Hemgenix (etranacogene dezaparvovec).

 It’s approved for adults who are currently undergoing factor 9 replacement therapy, have a historical or current life-threatening hemorrhage, or have recurrent and serious spontaneous bleeding episodes. But, per the prescribing information provided by the drugmaker CSL Behring, “Hemgenix is not intended for administration in women.”

Hemgenix is a one-time, single-dose gene therapy product. Given through an intravenous infusion, it contains a noninfectious viral vector, called an adeno-associated virus, carrying a gene for factor 9. Hemgenix works in the liver to produce the protein and increase blood levels of factor 9.

The safety and effectiveness of Hemgenix were evaluated in two studies of 57 adult men ages 19 to 75 with severe or moderately severe hemophilia B. In one study, with 54 participants, researchers found that subjects who took the gene therapy had:

  • Increases in factor 9 in their blood
  • A reduction in routine factor 9 replacement therapy
  • A 54 percent reduction in annualized bleeding rate compared with baseline

Adverse reactions to the therapy included:

  • Increases in liver enzymes
  • Headache
  • Mild infusion-related reactions
  • Flu-like symptoms
The list price of Hemgenix is $3.5 million per treatment per individual, making it one of the most expensive drugs in the world. Thus far, the drugmaker has presented data showing Hemgenix’s effects endure for two years after infusion.

Future research will determine how long its efficacy persists over time.

The Takeaway

  • Hemophilia B is caused by a lack of clotting factor 9.
  • The standard treatment is factor 9 replacement therapy.
  • Newer treatments include medicines that increase the level of clotting enzymes in the blood, and gene therapy, which provides a working copy of the faulty gene that causes hemophilia.
  • Hemophilia treatment centers can provide support and education for people who have hemophilia.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Data and Statistics on Hemophilia. Centers for Disease Control and Prevention. May 15, 2024.
  2. About Hemophilia. Centers for Disease Control and Prevention. March 5, 2025.
  3. Hemophilia B. National Bleeding Disorders Foundation.
  4. Hemophilia B. National Organization for Rare Disorders. October 15, 2024.
  5. Hemophilia B. MedlinePlus. March 31, 2024.
  6. FDA Approves New Treatment for Hemophilia A or B. U.S. Food and Drug Administration. October 11, 2024.
  7. U.S. FDA Approves Pfizer’s HYMPAVZI (marstacircimab-hncq) for the Treatment of Adults and Adolescents with Hemophilia A or B Without Inhibitors. Pfizer. October 11, 2024.
  8. FDA Approves Novel Treatment for Hemophilia A or B, with or without Factor Inhibitors. U.S. Food and Drug Administration. March 28, 2025.
  9. Treatment of Hemophilia. Centers for Disease Control and Prevention. November 13, 2024.
  10. Infusion Basics. National Bleeding Disorders Foundation.
  11. Patient Out-of-Pocket Expenses. National Bleeding Disorders Foundation.
  12. Albumin Blood Test. MedlinePlus. December 9, 2024.
  13. AlphaNine SD Product Information. Grifols.
  14. LABEL: PROFILNINE -factor ix complex kit. DailyMed. May 28, 2025.
  15. Products Licensed in the US. National Bleeding Disorders Foundation.
  16. IDELVION. U.S. Food and Drug Administration. June 20, 2023.
  17. MASAC Recommendations Concerning Products Licensed For The Treatment of Hemophilia and Other Bleeding Disorders (Revised February 2020). National Hemophilia Foundation. February 28, 2020.
  18. Testing for Inhibitors and Hemophilia. Centers for Disease Control and Prevention. May 15, 2024.
  19. Hemophilia Treatment Centers (HTCs). Centers for Disease Control and Prevention. May 15, 2024.
  20. Four Reasons to Establish Care at a Hemophilia Treatment Center. Great Lakes Hemophilia Foundation. March 10, 2022.
  21. Hemophilia Treatment Center (HTC) Directory. Centers for Disease Control and Prevention.
  22. Hemophilia. American Society of Gene & Cell Therapy. July 9, 2025.
  23. U.S. Food and Drug Administration approves CSL's HEMGENIX® (etranacogene dezaparvovec-drlb), the first gene therapy for hemophilia B. CSL. November 22, 2022.
  24. HEMGENIX: Prescribing Information. CSL. November 2022.
  25. CSL’s Novel Gene Therapy HEMGENIX® (etranacogene dezaparvovec-drlb) Demonstrates Durable Protection and Sustained Factor IX Activity Levels for People Living with Hemophilia B at 24-Months Post-Treatment. BioSpace. December 10, 2022.
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