Gene Therapy Proves Valuable For Men With Hemophilia B
Gene therapy boosted output of a blood clotting factor, improving quality of life in a group of six men with hemophilia B, a study from St. Jude Children's Research Hospital showed.
"It is a small trial in that only six patients have been treated thus far, but it has been rather successful and I think it will encourage further use of this approach in the very near future, both by us and others," senior author Dr. Andrew Davidoff, chairman of surgery at the Memphis hospital, told HealthDay. "At this point, we're a little shy of being able to call it a cure, but it's a good start."
Researchers used a "vector," a virus that doesn't lead to disease, to deliver a gene containing factor IX, the blood clotting protein, to the patients, two each of whom received a low-, medium- or high-dose. Later, factor IX levels rose in the patients from less than 1 percent to between 2 and 12 percent.
After treatment, four of the six were able to discontinue protein injections to prevent bleeding episodes, and have not spontaneously bled since. Two other patients have increased time between needing factor IX injections.
The hemophilia B gene variant bars blood from clotting normally, and about 1 in 25,000 males inherit it. Hemophilia A affects about 1 in 5,000 males born in the United States. Davidoff said the hemophilia A protein is much larger and more likely to cause the body to generate an immune respone.