Heart and blood disorders


Hemophilia is a rare bleeding disorder where one of the clotting factors is missing or deficient that affects your blood’s ability to clot normally.

The most common type of hemophilia is Hemophilia A. It is caused by a missing protein called factor VIII. This is a protein in the coagulation cascade – a series of reactions that occur in your blood and signal when it should clot.

What is hemophilia?

Hemophilia is the name given to a rare bleeding disorder that prevents your blood from clotting normally. When you have hemophilia, mild cuts and grazes will bleed for longer than usual before they clot. More seriously, if you have hemophilia you are at a greater risk of internal bleeding. Joints such as your knees, ankles and elbows can be at risk of internal bleeding, and so can your muscles, tissues and internal organs. If internal bleeding occurs in an organ, especially the brain, it can be life-threatening.

What causes hemophilia?

Hemophilia is usually inherited. It occurs because one of the clotting proteins needed to form blood clots in the body is missing or reduced.

The two main types of hemophilia are A and B. If you have hemophilia A, you're missing or have low levels of clotting factor VIII (8). About 8 out of 10 people who have hemophilia have type A. If you have hemophilia B, you're missing or have low levels of clotting factor IX (9).

Rarely, hemophilia can be acquired. "Acquired" means you aren't born with the disorder, but you develop it during your lifetime. This can happen if your body forms antibodies (proteins) that attack the clotting factors in your bloodstream. The antibodies can prevent the clotting factors from working.

There are a number of different types of hemophilia. Hemophilia A, also known as factor VIII deficiency or classic hemophilia, is the most common. If you have hemophilia A, you are missing factor VIII, which is a key protein in the coagulation cascade, a series of reactions that tell your blood when to clot. About 80 in 100 people with hemophilia have type A.

In other, rarer types of hemophilia, such as Hemophilia B, Hemophilia C and Von Willebrand disease, different clotting factors are missing.

Treating hemophilia

Although there is no cure for hemophilia, a treatment called substitution therapy has existed for several decades.

In substitution therapy, the missing coagulation factor protein is injected into blood stream. The injection is made by extracting the missing factor protein from either the plasma of donated blood or genetically modified cell cultures.

Using genetically modified cell cultures first became possible after the factor VIII gene was discovered in 1984. We were one of the first suppliers of a factor VIII product made from genetically modified cell cultures. It is considered to be safer than donor blood-derived injections because it cuts out any risk of infection. When plasma donors are used as a source for substitution therapy, there is a potential risk of blood-borne viruses being spread, despite the virus-inactivation measures that have been introduced.

Substitution therapy has been shown to help to protect you from joint bleeds if you have hemophilia. However, because the injected clotting factor protein is broken down in the body over time, it has to be injected several times a week.

Ongoing research

Bayer has numerous compounds in various stages of development for hemophilia A and other blood and bleeding disorders. Together, these compounds show our commitment to research and development for these conditions. If you have hemophilia or a similar bleeding disorder, talk to your doctor to find out the best treatment option for you.

Advice for patients

Each body reacts differently to medicines. Therefore it is impossible to tell which medicine works best for you. Please consult your physician.