A new type of gene therapy is showing promise in the treatment of hemophilia. Our health correspondent Dr. Emily Senay explains.
A new study recently conducted by researchers at Beth Israel Deaconess Medical Center in Boston examined a new form of gene therapy. It was used to treat six patients who suffered from hemophilia, a genetic disease that involves the X chromosome. The disease affects about 15,000 men in the United States.
People who suffer from hemophilia lack the proper amount of a blood-clotting protein called factor VIII. So their blood doesn't clot properly and they can bleed both internally and externally. Those who suffer from the most severe forms of hemophilia can spend up to $100,000 dollars a year on factor VIII replacement therapy. Severe hemophiliacs suffer a wide array of problems that can range from bleeding in the joints, which can cause arthritis, to spontaneous bleeding.
Dr. David Roth, MD, directed the study at Beth Israel Deaconess Medical Center in Boston. Six severe hemophiliacs took part in the study. Researchers took a skin sample. The factor VIII gene was then transferred into each individual cell in the skin sample by using a small electric shock. The cells that now contained healthy factor VIII genes were then cloned. In the final step, anywhere from 100,000 to 400,000 cells were surgically implanted into the fatty tissues of the patient's abdomen.
After the procedure, all six hemophiliacs were monitored for 1 year. This was a phase I study, which means that the main purpose was to see if it was safe. The study did conclude that it was safe and well tolerated by patients, and there were no side affects from the genetically altered cells.
The study also found that four of the six hemophiliacs had elevated factor VIII levels after receiving the modified cells. This increase coincided with a decrease in bleeding and a reduction in the amount of factor VIII needed to treat bleeding. Results lasted for as long as 10 months.
Unlike traditional gene therapy, which is a viral therapy and done in vivo--inside the body--the hemophilia gene therapy was a nonviral therapy and was done ex vivo--outside the body.
Viral therapy is used to treat cancer. They take a virus, insert into it a gene that can kill the cancer, and then inject the virus into the body of a patient. The virus attaches itself to the cancer, empties its contents, and kills the cancer.
What makes this study interesting is that they used a new approach to gene therapy. The conclusion here is that gene therapy is in its infancy and that researchers are coming up with innovative new approaches and ways to utilize gene therapy. As these forms of therapy develop they will someday affect our lives in significant ways.
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