Hemophilia is a rare, genetically inherited bleeding disorder that typically occurs in males. Individuals with hemophilia have little or no clotting factor, a protein produced in the liver that is required for normal blood clotting. Hemophilia can be mild, moderate or severe, depending on how much clotting factor is present in a patient’s blood. More severe disease can cause patients to experience life-threatening bleeding after an injury and long-term health problems, including joint damage.
The two most common types of hemophilia are hemophilia A (also called Factor VIII deficiency) and hemophilia B (or Factor IX deficiency). Moderate-to-severe hemophilia A affects over 12,000 people in the US and over 90,000 outside of the US. Moderate-to-severe hemophilia B affects approximately 3,000 and 18,000 in the US and the rest of the world, respectively.1
Currently, the primary treatment option for hemophilia is factor replacement therapy. Concentrates of clotting factor are administered intravenously to help replace the clotting factor that is missing or low. For patients with severe hemophilia, replacement therapy infusions are typically administered as often as three times a week, or more. This preventive therapy is usually initiated in patients at a young age and may need to be continued for life.
Gene therapy represents a major potential breakthrough in the way hemophilia is treated by replacing Factor IX for hemophilia B or Factor VIII for hemophilia A, which are required for normal blood clotting. Dimension’s proprietary AAV vector technology allows for systemic administration of the gene therapy, which has been shown in previous proof-of-concept clinical studies in hemophilia B to enable the liver to produce Factor IX. This approach may enable patients to reduce or discontinue replacement therapy infusions for an extended period of time.