What is haemophilia?
Haemophilia is a serious, inherited bleeding disorder in which a person’s blood does not clot properly, leading in severe cases to uncontrolled bleeding, either spontaneously or after minor trauma. While a person with haemophilia may not bleed more or faster than a person without haemophilia, they bleed for a longer period of time1 and the recurrent bleeds can lead to significant impairment, especially in their joints.
As an inherited disorder, haemophilia is passed down from parent to child and is carried on the X chromosome as a recessive trait, meaning that it is usually transmitted from mother to son. While it is possible for females to be affected by haemophilia, this is very rare and the largest portion of the haemophilia population is male.
Haemophilia A is the most common type of haemophilia2, affecting approximately 320,000 people around the world.3,4 People with haemophilia A either lack or have low levels of an essential protein known as factor VIII that plays a crucial role in blood clotting.
When a bleed occurs in a healthy person, factor VIII binds to factors IXa and X, which are critical steps in the formation of a blood clot and help stop bleeding. However, in a person with haemophilia A, the lack or decrease of factor VIII interrupts this process and affects the ability to form a clot.
Based upon the level of factor VIII that is missing from a person’s blood,5 haemophilia A is classified in severity into three categories – mild, moderate and severe. Approximately 50 – 60 per cent of people with haemophilia A have a severe form of the disorder6 and these people usually bleed frequently – once or twice a week – into their joints or muscles.7 These bleeds can present a significant health concern as they often cause pain and can lead to chronic swelling, deformity, reduced mobility, and long-term joint damage.8 In addition to impacting a person’s quality of life,9 these bleeds can be life threatening if they go into vital organs, such as the brain.10,11
Symptoms and diagnosis
Given the hereditary nature of haemophilia, the disorder is often diagnosed when patients are very young. Signs and symptoms may include:
- Bleeding into muscles and joints
- Spontaneous bleeding
- Sustained bleeding following a minor trauma or surgery12
Replacement factor VIII, either recombinant (genetically engineered) or derived from plasma, is the mainstay of treatment for haemophilia A. Most formulations require frequent intravenous infusions, usually at least a few times a week, which may be burdensome to patients13 or their caregivers. This may impact compliance,14,15 leading some patients to take their treatment ‘on-demand’ when a bleed occurs rather than preventatively to stop bleeds from happening in the first place.16
An additional limitation of the current treatment is the development of inhibitors, which are antibodies developed by the body’s immune system that can attack the replaced factor VIII,17because it is recognised as foreign. Inhibitors can make treatment with factor VIII replacement ineffective. As many as one in four (25–30%) people with severe haemophilia A develop inhibitors to factor VIII.18
Treatment options for people with inhibitors are limited. These patients may need more frequent treatment infusion as well as immune tolerance induction (ITI), where the patient is given very high doses of factor VIII over a long period of time so the immune system tolerates factor VIII. If ITI fails or if patients are not suitable for ITI, bypassing agents are another treatment option. Like factor VIII replacement, bypassing agents are given intravenously, and at an even higher frequency.19
For more than 20 years, Roche has been innovating and delivering medicines for people with diseases of the blood. Today, we are investing more than ever in our effort to bring innovative treatment options to people with diseases of the blood, including haemophilia A, and are committed to developing novel approaches to hopefully advance the management of these serious disorders.