Hemophilia

Hemophilia is a family of genetic diseases that result in a deficiency of a protein that is required for normal blood clotting—clotting factor VIII in hemophilia A or clotting factor IX in hemophilia B. ^1,3 Because the level of factor VIII or IX in the blood usually stays the same throughout life, hemophilia is a lifelong disease.⁴ It is an X-linked genetic disease.⁴

However, approximately one-third of all cases of hemophilia develop as a result of a spontaneous genetic mutation where there is no prior family history.⁵

There are different degrees of severity of hemophilia, depending on the amount of clotting factor in the blood. People with mild hemophilia usually have problems with bleeding only after surgery, dental procedures, and trauma, while people with severe hemophilia may experience spontaneous joint and muscle bleeding, typically beginning at a very young age, and prolonged bleeding after injuries, traumas, and surgery. People with moderate hemophilia may have occasional or frequent bleeding, depending on their clotting factor level.^1,3

Patients with hemophilia must be careful to avoid injuring themselves, since any injury may result in excessive bleeding. Bleeding can be life threatening if it occurs in the central nervous system, gastrointestinal system, neck or throat, or if it is associated with severe trauma.^1,3

While there is no cure for hemophilia, it can be treated using infusions to replace the missing clotting factor in the blood.⁴ Factor replacement therapies can be derived from human plasma, but since the 1990s, treatments have been available using recombinant DNA technology.¹ A non-coagulation factor-based treatment has been approved for patients with hemophilia A, and new approaches, such as gene therapy, are also being investigated.⁶

Approximately 400,000 people in the world are affected by hemophilia A and hemophilia B. Hemophilia A occurs in about one in every 5,000-10,000 male births, while hemophilia B occurs in about one in 25,000 male births.^1,7

It is less common for females to have severe hemophilia, but a girl or woman may be affected if she is a carrier of a defective FVIII or FIX gene, and the resulting FVIII or FIX level is low.⁸

The signs and symptoms of hemophilia A and hemophilia B are similar, and can include the following:^1,3

• Prolonged bleeding following an injury or surgery
• Spontaneous bleeding (ie, bleeding that occurs without an apparent cause), especially into the joints and muscles, leading to pain and swelling of the affected area
• Bruising, which is very common in children with hemophilia
• Blood in the urine or stool
• Heavy bleeding following circumcision
• Unexplained nosebleeds
• Serious bleeding episodes, including in the brain and digestive tract

Hemophilia A and B are diagnosed by blood tests that measure the level of coagulation activity for factors VIII (for hemophilia A) and IX (for hemophilia B).^1,3

Treatment can be administered at the time of a bleed, in anticipation of an activity that might prompt bleeding (eg, sports), or on a regular basis (prophylaxis) to prevent bleeding.⁵

Hemophilia treatment requires a team approach, involving a group of health care professionals who are experts in treating bleeding diseases, including hematologists, nurse specialists, physical therapists, social workers, and other medical professionals, such as dentists and orthopedic surgeons.⁵

While there is no cure for hemophilia yet, several treatment options are available to patients, which include infusing the missing clotting factor product directly into the vein.^4,5 It is critical to administer treatment as quickly as possible to prevent long-term damage.

Gene therapy is a novel approach to treatment that is being investigated in clinical trials.⁶ One type of gene therapy, called gene transfer, involves giving an individual with hemophilia a functional FVIII or FIX gene by an IV infusion. This approach to treatment, which holds the promise of eliminating the need for regular intravenous infusions of factor VIII of IX protein, may improve the patient experience.⁹

Pfizer is currently investigating gene therapies for both hemophilia A and hemophilia B, and also a non-factor-based treatment for hemophilia.

Better treatment has improved the prognosis and increased the lifespans of patients with hemophilia. Exercise, can strengthen muscles to help protect against spontaneous bleeds and joint damage. The severity of a patient’s hemophilia must be considered when selecting an exercise regimen.¹⁰ With knowledge, healthy choices, and proper treatment, more people with hemophilia are playing an active role in managing their disease.

In the developing world a large proportion of patients with hemophilia are either not diagnosed or don’t have access to effective treatments. Pfizer is working with the World Federation of Hemophilia (WFH) to improve the availability of medical care in the developing world through the WFH’s Twinning Program. Sponsored solely by Pfizer, this program pairs a hemophilia treatment center or patient advocacy organization in a developing country with a corresponding treatment center or patient organization in a developed one.