Author Interviews, Genetic Research, Hematology / 08.12.2020
Gene Therapy Liberates Hemophilia B Patients from Requiring Regular Infusions of Clotting Factor
MedicalResearch.com Interview with:
Steven Pipe, MD
Professor of Pediatrics and Pathology
Laurence A. Boxer Research Professor of Pediatrics and Communicable Diseases
Pediatric Medical Director, Hemophilia and Coagulation Disorders Program
Director, Special Coagulation Laboratory
University of Michigan
MedicalResearch.com: What is the background for this study?
Response: Hemophilia B is an inherited bleeding disorder where patients are missing clotting factor IX (9), a critical blood clotting protein. Patients with a severe deficiency are at risk for traumatic and spontaneous bleeds – primarily into joints. Repeated bleeding into joints causes more than acute pain and swelling but also leads to inflammatory and degenerative changes in joints that eventually leads to severe debilitating arthritis that can be crippling. To try to prevent this, patients as young as infants are placed on regular infusions of clotting factor IX concentrates. The relatively short half-life of factor IX means patients must infuse on average once to twice a week. These can only be delivered intravenously – parents and then patients themselves have to learn this. Prophylaxis must be continued lifelong to try to prevent bleeding events and protect joint health over the lifespan. This is a tremendous burden on the patient and their caregivers.
Even with regular prophylaxis, joint bleeds may still occur and arthropathy may still ensue. This is because the blood levels often reach critically low levels prior to the next infusion. Gene therapy aims to deliver a functional copy of the factor IX gene such that the patient’s own liver will make a continuous supply of factor IX that is delivered to the bloodstream. At steady state with levels close to or within the normal range, patients would no longer be subject to bleeding events and would not require prophylaxis any longer. We hope that such a one-time treatment would produced durable, “functionally curative” levels of factor IX.
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