The following questions and answers do not replace advice from your doctor.

Haemophilia B is a condition present from birth which affects the ability of the blood to clot. It means that you do not have enough of a protein called clotting factor IX (factor nine) in your blood.1

Only about 20% of people with haemophilia have haemophilia B. It is a rare condition affecting about one in every 50,000 males.2

The main symptoms are:2

  • a tendency to bruise easily especially in early childhood
  • excessive bleeding from cuts that can take a long time to stop
  • a tendency to bleed into joints and muscles causing pain, swelling and limitation of movement

Yes. Haemophilia B is either mild, moderate or severe, depending on the level of clotting factor IX in the blood.2

Haemophilia A is caused by a deficiency in clotting factor VIII (factor 8), whereas haemophilia B is caused by a deficiency in clotting factor IX (factor 9).2

An inhibitor is an antibody in our system that prevents factor replacement treatment working. It recognises and acts on the factor concentrate as a foreign body – stopping it from working and making bleeding more difficult to treat.3

The Haemophilia Society is a UK-wide charity for all those affected by bleeding disorders. You can find out more by visiting

Extended half-life products use new technology that makes them stay and act in your body for longer than traditional treatments for haemophilia B, which may mean less frequent injections.4,5

There is no cure for haemophilia B, but with the right care and treatment, you can still lead a full and active life.

Idelvion is a pale yellow to white powder. Reconstituted Idelvion is yellow to colourless in appearance.

Idelvion does not need to be stored in a refrigerator. Idelvion can be stored at room temperature (2-25°C). Do not store above 25°C. Do not freeze. Keep vials in the outer carton in order to protect from light.

  • Idelvion (not reconstituted) can be stored for up to 3 years
  • After reconstitution the product should be used immediately

Yes, based on research, factor nine levels of 5-10% are shown to control bleeding with prophylaxis.6

Research shows Idelvion keeps clotting factor nine levels above 5% for up to 14 days.7

People with haemophilia B have traditionally injected their medicine two or three times each week. But Idelvion stays in your body longer so you may not need to use it as often.7,8

This means less impact on your life as you may not need as many injections.