Hemophilia A medical therapy

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Fahd Yunus, M.D. [2]

Overview

There is no definitive treatment for Hemophilia A, the mainstay of therapy is supportive and preventative care. It is recommended that patients diagnosed with hemophilia be referred to hemophilia treatment centers (HTC), which provide coordinated care between physicians (usually hematologists), nurses, social workers and other staff who specialize in bleeding disorders.

Medical Therapy

Most haemophilia patients require regular supplementation with intravenous recombinant factor VIII, also known as replacement therapy. This is highly individually determined. Apart from "routine" supplementation, extra factor concentrate is given around surgical procedures and after trauma, as well as emergently during any bleeding episode. Recombinant factor VIII concentrates do not contain any plasma or albumin, and therefore do not carry the risk of transmitting bloodborne viruses.

Other therapeutic options include cryoprecipitate, fresh frozen plazma (FFP), desmopressin (DDAVP), and anti-fibrinoltytic agents.

• Cryoprecipitate contains moderately high concentrations of factor VIII and may be given for joint and muscle bleeds. However, as it is derived from blood it carries risk of viral contamination
• FFP (fresh frozen plasma) contains clotting factors VIII and IX at significantly less concentrations than cryoprecipitate. As such, it is not routinely recommended as first-line therapy for hemophiliacs with bleeding episodes, given that the high amount of volume required to correct the coagulation deficit may result in circulatory volume overload.
• DDAVP, or desmopressin, is a synthetic hormone which stimulates the release of factor VIII. It may be given to patients with mild, or sometimes moderate, hemophilia to treat minor bleeding
• Anti-fibrinolytic medications, most commonly epsilon aminocarproic acid, may be given orally or intravenously to prevent clots from being dissolved. It is often given orally prior to dental work to reduce risk of bleeding.
• Patients with hemophilia may also require transfusion of packed red blood cells if excessive bleeding results in anemia.

A particular therapeutic conundrum is the development of "inhibitor" antibodies against factor VIII due to frequent infusions.

• 20-30% of patients with severe hemophilia A develop antibodies to clotting factor VIII, called inhibitors.
• Inhibitors prevent replacement therapy from being effective as they target the recombinant factor VIII and prevent it from working.
• If a patient develops an inhibitor to factor VIII, physicians may either attempt to infuse larger doses of recombinant clotting factor, or try different clotting factor sources.
• These antibodies may self-resolve with time. No definitive therapy exists otherwise for patients who develop inhibitors to factor VIII.
• Recently, Immune Tolerance Induction (ITI) therapy is being researched as a means of helping patients with haemophilia and factor inhibitors. ITI involves overcoming the immune reaction and desensitizing the body to the foreign factor concentrate infusion. ITI is expensive, time-intensive, and requires the oversight of multiple medical professionals, and is best coordinated at a hemophilia treatment center (HTC).