Treatment of 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.

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.

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. The two main replacement therapies are plasma-derived factor concentrates and recombinant factor concentrates, which are infused into the bloodstream via a vein in the arm.

Plasma-Derived Factor 9 Concentrates

Plasma-derived factor 9 concentrates are derived from human donations of blood or plasma.

All donated blood or plasma go through tests 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, according to the CDC.

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, according to DailyMed.

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Recombinant Factor 9 Concentrates

Available recombinant factor 9 concentrates include:

• Alprolix
• Benefix
• Idelvion, which also contains albumin, according to the U.S. Food and Drug Administration (FDA)

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• Ixinity
• Rebinyn
• Rixubis

People with hemophilia are advised to get tested for inhibitors yearly so that serious health problems can be prevented. 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: The NBDF states that a person with an inhibitor usually has medical expenses of more than $1 million per year.

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 blood clots from being broken down. It’s typically prescribed to treat heavy menstrual bleeding in girls and women age 12 and older to reduce menstrual blood loss.

The 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.

• Physicians, in particular hematologists (blood specialists)
• Lab medical technologists
• Pathologists (body tissue and fluids specialists)
• Orthopedists (bones, joints, and muscles 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 compared with 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.

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. It expresses in the liver to produce the protein and increase blood levels of factor 9.

According to the FDA, the safety and effectiveness of Hemgenix were evaluated in two studies of 57 adult men ages 18 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 Takeaway

• Hemophilia B is caused by a lack of clotting factor 9.
• The standard treatment is factor 9 replacement therapy.
• Newer treatments include medicine to 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.