Transfusions continued until a year after the treatment, Leboulch said. "One year after the treatment he became transfusion-independent," he said. "That has been the case for over two years now."
For the study, Leboulch's team worked on a modified virus and removed all the viral genes. They then replaced those genes with a so-called globin gene. In addition, they added factors so the gene would act only on red blood cells, where the iron-rich protein known as hemoglobin normally carries oxygen throughout the body.
This new "gene" was then injected into the patient, where it went on to repair the damaged globin gene and started producing normal hemoglobin, Leboulch said.
"This is one more example of a gene therapy that starts to show a clinical benefit for patients," he said.
However, Leboulch is cautious. "This is the first patient in the trial. Of course we need to do more patients and see what happens," he said.
Leboulch noted another problem with gene therapy: the inability to control all the effects a new gene will have in the body. The globin gene, for example, appears to link to another gene that is involved in cell growth, causing a mild expansion of blood stem cells in the patient's body. This could account for some therapeutic benefits, but might also be a precursor to cancer, the researchers noted.
"So far there is no sign of any abnormality," Leboulch said.
Dr. Francoise Bernaudin, a clinical hematologist who has followed the patient since early childhood, said it was "wonderful to see that this young man is for now free of transfusions and injections for iron chelation.
"He is happy to have a normal life back, and for the first time has a full-time job as a cook in a main restaurant in Paris," said Bernaudin in a news release on behalf of bluebird bio, developer of the LentiGlobin gene therapy treatment that the researchers are using. Th
All rights reserved