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French gene therapy trial suspended again

31 January 2005
By BioNews
Appeared in BioNews 293

A gene therapy trial for an inherited immune deficiency disorder has been suspended again, following the appearance of complications in a third child. Eleven patients affected by X-linked severe combined immunodeficiency disorder (X-SCID) have so far been treated by the team, based at the Necker Hospital in Paris. While most have responded extremely well to the therapy, the trial was suspended in late 2002, after two patients developed symptoms of leukaemia. One of these boys is now in remission, but the other has since died. The AFSSAPS (French Agency for Health Product Safety) gave permission for the trial to restart in May 2004, but has now suspended the experimental treatment again.

Children affected by SCID have a faulty gene that means they have no working immune system, so their bodies cannot fight infections. This life-threatening condition is sometimes called 'bubble boy' disease, as unless they can be successfully treated with a matched bone marrow transplant, patients must spend their lives in a sterile environment. To carry out the gene therapy treatment, the French researchers harvested bone marrow from the patients, from which they isolated blood stem cells. They then infected these cells with a retrovirus (a virus that inserts its genetic material into the host cell's DNA) carrying a working gene, before returning the modified cells back to the patients.

Scientists think that the leukaemia in the two patients reported in 2002 was caused by the gene therapy, although other factors may also have contributed. In both cases, researchers found that the retrovirus had inserted its genetic material close to the 'on-switch' of a cancer-causing gene called LMO2. It is thought that this event caused the unregulated growth of the bone marrow cells, which in turn triggered the leukaemia. Now, a patient who was treated in April 2002, at the age of nine months, is also showing signs of 'lymphoproliferation' - overgrowth of white blood cells. The AFSSAPS has suspended the trial while the causes of this latest complication are investigated, French newspapers reported last week.

Gene therapy: new complication for 'bubble boy'
Genethiqe press review |  31 January 2005
Survenue d'une troisieme complication dans l'essai clinique  de therapie genique DICS X
AFSSAPS |  24 January 2005
2 February 2009 - by Dr Megan Allyse 
Researchers in Italy and Israel have announced that they have successfully used gene therapy to treat ten children who suffer from a rare form of severe combined immunodeficiency (SCID) called ADA-SCID. The trial marks one of the first successful uses of gene therapy since past trials of...
27 April 2006 - by BioNews 
Replacement genes used to treat an inherited immune disorder could trigger cancer, new research carried out on rodents suggests. The study, published in the journal Nature, shows that treating mice with a normal copy of the gene defective in X-linked severe combined immune deficiency (X-SCID) results in cancer of the...
8 April 2005 - by BioNews 
A gene therapy technique that repairs faulty genes by 'editing' their DNA could lead to new treatments for inherited blood disorders and HIV, say US researchers. The approach could help address safety concerns over current gene therapy methods, many of which rely on specially adapted viruses to deliver working genes...
13 March 2005 - by BioNews 
Doctors at Great Ormond Street Hospital (GOSH) for Children and the Institute of Child Health have successfully treated a second disease using pioneering gene therapy treatment. The four-year old boy who received the therapy was affected by ada-SCID, a life-threatening immune deficiency condition. He is now attending pre-school and living...
7 March 2005 - by BioNews 
The US Food and Drug Administration (FDA) has recommended that gene therapy treatments for an inherited immune disorder are limited to those who have no alternative. The move follows news that a third child in a similar French trial has developed leukaemia. The trial for X-linked severe combined immunodeficiency disorder...
17 December 2004 - by BioNews 
Four children who received gene therapy for a severe inherited immune disorder are now all at home living normal lives, UK scientists report. The boys, who were affected by severe combined immunodeficiency (SCID), received the pioneering treatment at Great Ormond Street Hospital in London. In a commentary accompanying the study...
14 June 2004 - by BioNews 
A French gene therapy trial halted after two participants developed leukaemia looks set to restart after a 22-month suspension, reports Nature. Scientists at the Necker hospital in Paris successfully treated nine children with an inherited immune system disorder called X-linked severe combined immune deficiency (X-SCID). But the trial, along...
17 October 2003 - by BioNews 
US and European scientists have published results confirming that a gene therapy technique triggered leukaemia in two boys taking part in a trial at the Necker hospital, Paris. Their findings, which appear in Science, show that the virus used to deliver the therapeutic gene activated a cancer-causing gene. Eleven boys...
21 July 2003 - by BioNews 
A second patient in a gene therapy trial taking place at Great Ormond Street Hospital in London has been successfully treated, his parents and doctors announced last week. Christopher Reid, now two years old, received gene therapy for the immune system disorder X-linked severe combined immune deficiency (X-SCID) in December...
16 December 2002 - by BioNews 
US gene therapy trials for a rare immune disorder, suspended after a patient in a similar French trial developed a leukaemia-like disease, should now go ahead, says the Recombinant DNA Advisory Committee (RAC). In October, gene therapy trials for severe combined immunodeficiency (SCID) were halted in several countries, after scientists...
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