In a preliminary study, six patients in England were
successfully treated by gene therapy for the blood-clotting
disease hemophilia B. Researchers injected each patient with the
correct form of the gene that makes the needed substance that
helps blood to clot, called a clotting factor. “I think it’s a
significant advancement in gene therapy and a treatment for
hemophilia,” said Mark Kay, Professor at Stanford’s School of
Medicine and a co-author of the study. “It’s been over a year
for some of the patients and they are continuing to make the
[clotting] factor. We have to start at low doses and work our
way up. We have patients that are at 10 percent level for half a
year.” That 10 percent is remarkable. In hemophilia, people with
a severe form of the disease have less than one percent of the
clotting factor. Those with 10 percent are often able to live a
normal life.