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.