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Gene therapy studies suspended after death
French experiment worries U.S. experts
By Thomas H. Maugh II
Tribune Newspapers: Los Angeles Times
March 4, 2005 - Federal authorities have suspended three gene therapy experiments after news that a third child in a similar French study has developed leukemia and that one of the three has died.
A Food and Drug Administration advisory panel is to meet in suburban Washington on Friday in an effort to determine whether the French cases are an isolated incident caused by the specific gene being used in the therapy or a precursor of problems that will affect all gene therapy attempts.
Experts don't expect an immediate consensus from the advisory panel, but there appears to be a growing feeling among researchers that the problem is of limited scope and reflects the combination of the virus and gene used by the French. Experiments using other genes have been free of adverse effects.
Most of the researchers involved will be gathering in Washington on March 15 for a separate meeting sponsored by the National Institutes of Health Recombinant DNA Advisory Committee. They are scheduled to discuss their results to date. Despite the three leukemia cases, the results have been promising.
The experiments in question have involved treatments for severe combined immunodeficiency disease, or SCID, a potentially fatal genetic disorder that leaves its victims susceptible to life-threatening infections. The best-known example of the disease was David, the Houston "Bubble Boy" who lived for 12 years in a sterile enclosure to keep infections out.
Dr. Alain Fischer of Necker Hospital in Paris has been treating patients with so-called X-linked SCID, which is caused by a defective gene called GammaC. Fischer put a healthy form of the gene in a modified mouse leukemia virus, which was used to insert the gene into embryonic blood cells that are then infused into the patient.
Fischer has treated 17 patients, and virtually all have shown major improvement--if not a cure. But two years ago, Fischer said that two of the patients developed leukemia, presumably as a result of the treatment.
The FDA suspended 27 gene therapy trials in the United States but eventually allowed them to proceed again after concluding that there were special circumstances in the cancer victims. Both were below the age of 2 and received large doses of cells.
In recent weeks, Fischer revealed that one of the two original leukemia victims died of the disease and that a third child apparently contracted it. That child was older than the first two and received a lower dose of altered cells.
The FDA has temporarily shut down three studies examining treatments for SCID.
One of the studies is run by Dr. Harry Malech and Dr. Jennifer Puck of the National Institute of Allergy and Infectious Diseases. A second is run by Dr. Donald Kohn of the Keck School of Medicine at the University of Southern California. The third is run by Dr. Kenneth Weinberg of Keck.
FDA panel says proceed cautiously up to two gene therapy trials
Author : Martin Booth
News Category : Health
2005-03-06 - There were no surprises at the Food and Drug Administration advisory panel committee meeting to review the gene therapy experiments. Two trials being held at the National Institutes of Health and at the University of Southern California have been asked to see that all avenues of treatment be explored before continuing the experiments.
However, the FDA did allow one experiment that was being carried out at the USC since the disease in question is a variation of SCID that differs from the strain being treated by French researchers.
Dr. Mahendra Rao, chairman of the FDA's Cellular, Tissue and Gene Therapies Advisory Committee, said that the meeting was held in the backdrop of a third child developing leukemia in France.
However, he said that the FDA had not set a schedule to act on the panel's recommendations.