Gene Therapy May Reverse Hemophilia
A Single Treatment Allowed Patients With Hemophilia to Stop Regular Injections
Hope on the Horizon for Hemophilia and Other Diseases continued...
“We have made a significant impact on the severity of the disease,” Davidoff tells WebMD. “We are looking to cure patients, and I think with improvements in the vector and higher doses, we will be able to cure them.”
Before they were enrolled in the study, the six men all had levels of FIX protein that were less than 1%. After the gene therapy, their FIX levels improved to 2% to 11%.
That’s high enough to prevent spontaneous bleeding events. But it’s not enough clotting factor to keep them out of danger during surgery, for example, or in the event of other significant trauma.
Researchers think they may be able to give people with hemophilia B higher doses of the altered virus to help boost FIX levels even more.
But it’s unclear how much people will be able to tolerate.
In this study, patients who got the highest doses made the most FIX. But they also saw their liver enzymes spike, a sign of inflammation.
“We were able to control this inflammation with a very short course of steroids,” says study researcher Amit C. Nathwani, MBChB, PhD, a hematologist at University College London.
After steroid treatment, liver enzymes returned to normal. And patients continued to make FIX protein on their own, though their levels dropped slightly.
It’s also not clear how long the treatments may last.
All patients who got the gene therapy continue to make FIX protein. Some have been followed for nearly two years.
But as liver cells die, the treatment could wear off. In animal studies, results of gene therapies that target liver cells have lasted for 10 years or more.
Even if it’s temporary, the gene therapy is likely to save money. If it is approved by the FDA, the treatment is estimated to cost around $30,000 per patient.
It may also turn out to be safer than injecting blood products. In the 1980s, many hemophiliacs were infected with HIV after being treated with clotting factors that contained the virus.
Nathwani says many people with hemophilia in developing countries continue to face that risk, if they are able to get treatment at all.
“Eighty percent of hemophilia patients around the world have no access to treatment,” he says. “This is one of the reasons why we wanted to develop a simple gene transfer approach,” which could be delivered in almost any clinical setting, he says. “This is life changing.”