Therapeutic treatment

As the word denotes, prophylactic therapy aims to prevent bleeding episodes, i.e. to prevent bleeding through the long-term retention of satisfactory levels of coagulation factor in the blood. This is achieved by regular intravenous administration of treatment containing the relevant agent, according to physician’s instructions.

Alternatively, prophylactic therapy may include subcutaneous administration of a molecule that mimics the effect of factor VIII.

A major complication of replacement therapy is the development of inhibitors against coagulation factors administered as treatment. Inhibitors are antibodies developed by the body against the coagulation factors administered as treatment. In this way, the body "fights" the agent that receives through intravenous treatment (factor VIII or IX) because it recognizes it as "intruder" and develops antibodies to "inactivate" it.

Inhibitors of factor VIII are the most common and occur in about a third of people with severe haemophilia A and in about 1 in 50 people with mild or moderate haemophilia A.

Typically, this is developed during childhood in individuals with severe haemophilia A and later in life to those with milder conditions. Inhibitors destroy both the coagulation factor administered as treatment and any other coagulation factor already present in the body.

This is a serious complication of treatment, because if, for example, a person with haemophilia A develops an inhibitor of factor VIII, inhibitors will "inactivate" the total amount of factor VIII present in the body and, consequently, the efficacy of treatment will be reduced.

So, aren't there any good news for people with inhibitors?

Of course, there are! In about two-thirds of the cases, the inhibitor disappears on its own or by the application of a treatment known as immune tolerance therapy (ITT) or immune tolerance induction (ITI). In cases of severe haemophilia A with persistent inhibitors in an effort to control bleeding, bypassing agents are administered, which contain other factors that can stimulate the formation of a clot and stop the bleeding.

Alternatively, haemophilia A patients with inhibitors against factor VIII may receive a subcutaneous prophylactic therapy with a molecule that mimics the activity of factor VIII.