What is haemophilia A?

Find out more about haemophilia A and the clotting cascade

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The clotting cascade

There are things in your blood called clotting factors that work together to make a clot. A clot helps stop bleeding. Three of these are factor IXa (pronounced activated factor 9), factor VIII (pronounced factor 8) and factor X (pronounced factor 10).

Clotting factors interact with each other in a sequence – think of them like a set of dominoes.

Each clotting factor switches on the next one. When all the clotting factors have been switched on a clot is formed.

If you have haemophilia A, your blood does not clot properly. People with haemophilia A do not have enough of one of these blood clotting factors called factor VIII.

This is a bit like having a domino missing.

Haemophilia A is described as mild, moderate or severe, depending on how much factor VIII is in the blood. People with severe haemophilia A, like Jack, have less than 1% factor VIII, and people with moderate haemophilia A, like Ted, have between 1-5% factor VIII.

Some people with moderate haemophilia A can bleed more than others. Doctors and nurses call this having a “severe bleeding phenotype”.

Factor VIII replacement therapy is used to replace missing factor VIII. It can help make your blood clot and stop bleeds. You may have already used factor VIII replacement therapy to treat a bleed, or may have taken it regularly to try and prevent bleeds from happening.

Antibodies

Antibodies are a normal part of your blood that help fight infection. They help to protect you by recognising and sticking to things that shouldn’t be in your body, such as bacteria or ‘germs’.

Antibodies can also be made in a laboratory and used as medicines.

Hemlibra is a type of antibody, called a monoclonal antibody that can help people with severe or moderate haemophilia A.

Hemlibra sticks to two clotting factors, factor IXa (activated factor 9) and factor X (factor 10).

HOW DOES HEMLIBRA WORK?

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