Gene Therapy Used
To Successfully Treat 2 Patients
By GAUTAM NAIK
April 3, 2006; Page B6
LONDON -- A team of international scientists has used gene therapy to successfully treat two patients with a rare but deadly disease of the immune system, marking a small step in the push toward DNA-based medicine.
In a study published yesterday in the journal Nature Medicine, researchers described how they introduced a corrective gene to undo the damage caused by a form of chronic granulomatous disease, or CGD. The rare affliction, which is more commonly inherited by men, makes patients extremely vulnerable to infections.
"Gene therapy has continued to be difficult, but we are making progress," said Christof von Kalle, professor at the Cincinnati Children's Hospital Medical Center and at the National Center for Tumor Diseases Heidelberg in Germany. Dr. von Kalle is one of several authors of the Nature Medicine study.
Critics have suggested that gene therapy faltered because it moved too quickly from the lab into clinical trials. The field suffered a setback in 1999 with the death of a study volunteer at the University of Pennsylvania. A few years ago, 28 children participated in European gene-therapy trials aimed at treating another rare disorder called severe combined immunodeficiency, or SCID. Of the 28 children, 24 were deemed to be successfully treated, but three others developed a leukemia-like disease.
In the latest gene-therapy experiment, conducted by researchers in Germany, Switzerland, Britain and the U.S., two men with CGD were treated with gene therapy for 1½ years. Each of the two patients had inherited a defective gene that makes it difficult for their bodies to produce a particular enzyme. As a result, their myeloid cells, a form of white-blood cell, can't mount the appropriate response against fungal or bacterial infections.
To fix the problem, researchers used a virus to ferry corrective genes for the enzyme into the patients. The appropriate genes got switched on. But in a surprise to the scientists, the gene-corrected blood cells also tripled in number, improving the performance of the therapy.
Clinically, both patients are in good shape and no longer have to take round-the-clock antibiotics, Dr. von Kalle said. Abscesses that had formed in the lungs of one patient and in the liver of the other have disappeared. So far, neither patient is suffering negative side effects, he said.
The experiment is one of the first to show that gene therapy can successfully treat diseases of the myeloid system. Scientists refrain from pronouncing their achievement a cure, until they verify the effects last over time. |
