Hemophilia medical therapy

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]

Overview

The mainstay of therapy for hemophilia is blood clotting factor replacement therapy.

Medical Therapy

Blood Clotting factors

• The main treatment for hemophilia is called replacement therapy. Concentrates of clotting factor VIII (for hemophilia A) or clotting factor IX (for hemophilia B) are slowly dripped or injected into a vein. These infusions help replace the clotting factor that's missing or low. Clotting factor concentrates can be made from human blood. The blood is treated to prevent the spread of diseases, such as hepatitis. With the current methods of screening and treating donated blood, the risk of getting an infectious disease from human clotting factors is very small.
• To further reduce the risk, you or your child can take clotting factor concentrates that aren't made from human blood. These are called recombinant clotting factors. Clotting factors are easy to store, mix, and use at home—it only takes about 15 minutes to receive the factor.
• You may have replacement therapy on a regular basis to prevent bleeding. This is called preventive or prophylactic therapy. Or, you may only need replacement therapy to stop bleeding when it occurs. This use of the treatment, on an as-needed basis, is called demand therapy. Demand therapy is less intensive and expensive than preventive therapy. However, there's a risk that bleeding will cause damage before you receive the demand therapy.
• The two main types of clotting factor concentrates available are:
  • Plasma-Derived Factor Concentrates -Plasma is the liquid part of blood. It is pale yellow or straw colored and contains proteins such as antibodies, albumin and clotting factors. Several factor concentrates that are made from human plasma proteins are available. All blood and parts of blood, such as plasma, are routinely tested for the viruses. The clotting proteins are separated from other parts of the plasma, purified, and made into a freeze-dried product. This product is tested and treated to kill any potential viruses before it is packaged for use.
  • Recombinant Factor Concentrates- Until 1992, all factor replacement products were made from human plasma. In 1992, the U.S. Food and Drug Administration (FDA) approved recombinant factor VIII (8) concentrate, which does not come from human plasma. The concentrate is genetically engineered using DNA technology. Commercially prepared factor concentrates are treated to remove or inactivate blood borne viruses. In addition, recombinant factors VIII (8) and factor IX (9) are available that do not contain any plasma or albumin and, therefore, cannot transmit any blood borne viruses.

The products can be used as needed when a person is bleeding or they can be used on a regular basis to prevent bleeds from occurring. Today, people with hemophilia and their families can learn how to give their own clotting factor at home. Giving factor at home means that bleeds can be treated quicker, resulting in less serious bleeding and fewer side effects.

• Other treatment products:
  • DDAVP® (Desmopressin Acetate)-DDAVP® is a chemical that is similar to a hormone that occurs naturally in the body. It releases factor VIII (8) from where it is stored in the body tissues. For people with mild, and some cases of moderate hemophilia, this can work to increase their own factor VIII (8) levels so that they do not have to use clotting factor. This medicine can be given through a vein (DDAVP®) or through nasal spray (Stimate®).
  • Amicar® (Epsilon Aminocaproic Acid)-Amicar® is a chemical that can be given in a vein or by mouth (as a pill or a liquid). It prevents clots from breaking down, resulting in a firmer clot. It is often used for bleeding in the mouth or after a tooth has been removed because it blocks an enzyme in the saliva that breaks down clots.
  • Cryoprecipitate-Cryoprecipitate is a substance that comes from thawing fresh frozen plasma. It is rich in factor VIII (8) and was commonly used to control serious bleeding in the past. However, because there is no method to kill viruses, such as HIV andhepatitis, in cryoprecipitate it is no longer used as the current standard of treatment in the U.S. It is, however, still used in most developing countries.

Gene Therapy

• Researchers are trying to find ways to correct the faulty genes that cause hemophilia. Gene therapy hasn't yet developed to the point that it's an accepted treatment for hemophilia. However, researchers continue to test gene therapy in clinical trials.For more information, go to the "Clinical Trials" section of this article. On 10 December 2011, a team of British and American investigators reported the successful treatment of haemophilia B using gene therapy. The investigators inserted the F9 gene into an adeno-associated virus-8 vector, which has a propensity for the liver, where factor 9 is produced, and remains outside the chromosomes so as not to disrupt other genes. The transduced virus was infused intravenously. To prevent rejection, the people were primed with steroids to suppress their immune response.
• In October 2013, the Royal Free London NHS Foundation Trust in London reported that after treating six people with hemophilia in early 2011 with the genetically modified adeno-associated virus, over two years later all were still producing blood plasma clotting factor.

Complications of replacement therapy include

• Developing antibodies (proteins) that attack the clotting factor
• Developing viral infections from human clotting factors
• Damage to joints, muscles, or other parts of the body resulting from delays in treatment