Disease Areas


Discovering safe and effective treatments for people living with hemophilia and other rare bleeding disorders


What is hemophilia?

Hemophilia is a rare and serious X-chromosome linked congenital bleeding disorder that affects the blood's ability to clot, meaning that people with hemophilia bleed for a longer time than normal.

To understand hemophilia, it is helpful to know how the body normally works when it comes to stopping a bleed. When a person bleeds, 13 different proteins—called clotting factors—work together to form a blood clot.

In people living with hemophilia, one of the clotting factors is missing or reduced, which prevents this process from working. They have trouble forming blood clots—so it’s harder to stop bleeds when they happen.

How do people get hemophilia?

People living with hemophilia are typically born with it. In the majority of these cases, it is passed to a child from the mother's side of the family. Sometimes, a person may develop hemophilia without any family history. In fact, nearly one-third of hemophilia cases are not inherited and have no family history of the disease. Since the genes for coagulation factors are on the X chromosome, hemophilia mainly affects males who inherit an affected maternal X chromosome.

Due to a lack of bleeding at birth or because the family doesn't have a history of hemophilia, some people who have hemophilia are not diagnosed as newborns.

Two types of hemophilia


of people with hemophilia have hemophilia A. Also known as factor VIII (8) deficiency, it is caused by a lack of the clotting factor known as factor VIII.


of people with hemophilia have hemophilia B. Also called factor IX (9) deficiency, it’s caused by a lack of—you guessed it—factor IX. 

Mild, moderate, or severe hemophilia—what do they mean?

Mild 5-40%

Mild hemophilia means a factor VIII or IX level ranging from 5% up to 40% of normal blood levels

Moderate 1-5%

Moderate hemophilia refers to factor VIII or IX level ranging from 1% up to 5% of normal blood levels

Severe <1%

Severe hemophilia means a person has a factor VIII or IX level below 1% of normal blood levels

Did you know?

Hemophilia A affects 1 in 5000 male births in the United States.

Living with hemophilia and rare bleeding disorders

Since hemophilia and rare bleeding disorders are associated with several types of coagulation factors, there are different treatments. Current therapies are administered by infusion therapy injected into a vein or administered subcutaneously.

Replacement therapy can be given to combat a bleeding episode that is in progress. Or, it can also be administered at home on a regular schedule to help prevent bleeding episodes. For some people living with hemophilia, they must receive continuous replacement therapy.

Haemophilia research

Advancing treatments in hemophilia and in rare blood disorders

We combine our experience in protein design with collaborations in the global scientific community to discover and develop effective and safe medicines for people with hemophilia and other rare bleeding disorders.

Our scientists are exploring innovative, long-acting and subcutaneous treatment solutions for hemophilia and rare blood disorders. These solutions are aimed at reducing the current treatment burden and improving clinical outcomes. They will be complemented by research into oral treatments and gene therapy.

We strive for offering better quality of life to people living with hemophilia and other bleeding disorders.

We often work in partnerships to discover novel targets and innovative compounds and technologies that address unmet medical needs. 

Explore our ambitious R&D pipeline.

The spectrum of bleeding disorders

Along with hemophilia A and B, 15 other bleeding disorders have been identified. What makes them different?