Adults with hemophilia B saw their number of bleeding episodes drop by an average of 71 percent after a single infusion of gene therapy , according to the results of an international Phase III clinical trial published today in the New England Journal of Medicine by researchers from the University of Pennsylvania Perelman School of Medicine and a multicenter group of investigators. Hemophilia is a genetic disorder that limits the blood's ability to clot and affects around 30,000 people in the United States, mostly males. Left untreated, it can cause spontaneous bleeding, particularly internal bleeding into the joints, which, over time, can cause painful joint damage and mobility issues.
Hemophilia B is caused by a lack of clotting factor IX. The gene therapy enables the liver to create factor IX, which allows the blood to clot and protects patients from frequent bleeds. "What we saw from patients in this study was that within a few days of receiving the gene therapy infusion, it took root, and their bodies started making factor IX for the first time in their lives," said study investigator and lead author Adam Cuker, MD, MS, section chief for Hematology, and clinical director of the Penn Blood Disorders Center and the Penn Comprehensive Hemophilia Program.
"We always want to be careful about using the word 'cure' especially until we have longer follow-up data, but for many of these patients, it's been life changing." After at least one year of follow-up, participants in the st.