About Hemophilia
ABOUT HEMOPHILIA
Hemophilia is a rare disorder in which blood doesn’t clot in the typical way because it doesn’t have enough blood-clotting proteins (clotting factors).
The two most common types of hemophilia are categorized as types A and B. These conditions are often inherited, occurring because of gene variations that affect different blood clotting factors. Both have similar symptoms, including bruising and bleeding into joints, which causes stiffness, pain, and mobility issues, and bleeding after procedures such as dental surgery.
Hemophilia is considered a good candidate for gene therapy because it is a monogenic disorder (which means it is caused by an alteration to a single gene) and even a minimal increase in clotting factor can significantly improve quality of life.
Difference Between Hemophilia A and Hemophilia B
The main difference between hemophilia A and hemophilia B lies in the clotting factor that’s deficient. Hemophilia A—the most common type of hemophilia—is caused by a lack of blood clotting factor VIII, whereas hemophilia B is caused by a lack of factor IX. Furthermore, the gene that causes hemophilia B is both small in size and structurally simpler in comparison to hemophilia A.
In hemophilia A, a functional F8 gene is delivered to the liver, allowing it to start creating the missing or nonworking factor VIII proteins that cause the disorder. However, the way gene therapy for hemophilia A works is slightly different, since factor VIII is produced by different liver cells and tissues than those that produce factor IX.
For people with hemophilia B, gene therapy targets liver cells, known as hepatocytes, where factor IX proteins are naturally made. By delivering a functional F9 gene straight to the liver, it enables a person to start creating their own factor IX proteins that are missing or not working and causing the disorder.
ABOUT GENE THERAPY
Although the concept of gene therapy is not new, it is an innovative treatment option compared to traditional therapies as the first gene therapy was approved by the U.S. Food and Drug Administration (FDA) in 2017. As of 2024, there are 38 cellular and gene therapies approved by the FDA. These therapies cover a range of conditions, from certain types of cancers to genetic disorders such as hemophilia.
How Gene Therapies Work for Hemophilia
Gene therapies for hemophilia introduce a working, or functioning, gene into the body, which allows people with hemophilia to produce their own factor, which can lower the risk of bleeding and reduce or eliminate the need for ongoing, regular prophylactic treatment.
Candidate Screening for Gene Therapy
There are various factors involved in understanding if someone may be the right candidate for gene therapy, including current course of treatment, the severity of the condition, and the types of bleeding episodes one may experience. There are also pre-screening tests to check overall liver health and possible adeno-associated virus (AAV) neutralizing antibody levels. If a person tests positive for AAV neutralizing antibodies, they should discuss their gene therapy treatment options with their doctor.
How Gene Therapies for Hemophilia Are Administered
These gene therapies are administered via a one-time IV infusion, which takes about one to two hours, or longer depending on the treatment. Once administration is completed, patients will stay for monitoring for at least three hours. Following administration, regular lab tests are required to track progress including overall health, liver function, and factor activity level. These can often be completed at a local lab.
Cost of Gene Therapies for Hemophilia
Cost for treatment will vary based on coverage policies and eligibility for financial assistance programs. Payers covering the vast majority of the U.S. population have established clear medical policies for gene therapy. Additionally, manufacturers offer copay assistance programs, which may allow people with commercial insurance to pay $0 out-of-pocket for treatment.
For more information on gene therapy, visit BeyondHemB.com