Many people around the world have the disease 1 in 5,000 boys are born with hemophilia A, the more common of the two forms.
Hemophilia treatment consists of infusing the missing protein into a patient's blood. But in 25 percent of patients, the immune system rejects the therapy and makes inhibitors that stop the clotting factor from taking effect.
In hemophilia B, up to 4 percent of patients develop inhibitors to the protein therapy and many develop severe systemic allergic reactions, called anaphylaxis, which can be life-threatening.
"If the very protein that you administer to the patient is neutralized, it's as if you haven't administered any protein at all," said Thierry Vandendriessche, Ph.D., an associate professor of medicine at the University of Leuven in Belgium, and president of the European Society of Gene Cell Therapy. He was not involved in the study.
Because treatment itself poses a potential threat to life, it has to be done in a hospital setting under supervision. That makes it an expensive enterprise that often includes blood transfusions and hospital stays costing up to $1 million. Average treatment costs are $60,000 to $150,000 a year, according to the National Hemophilia Foundation.
To help patients tolerate therapy, doctors try to exhaust patients' immune systems by administering the therapeutic protein intravenously at frequent intervals and for long periods until the body no longer responds by producing inhibitors. While that brute force approach works for hemophilia A, it often doesn't for hemophilia B, in which patients risk death from anaphylactic shock if exposed to the protein therapy.
To find a new, gentler approach to developing tolerance, Herzog teamed with Henry Dani
|Contact: Czerne M. Reid|
University of Florida