JUST when things were starting to look rosier for gene therapy, a key clinical trial in France has suffered a renewed blow. The trial was about to resume, having been suspended since January 2003 because two of the patients developed leukaemia. Now a third boy may have the disease.
The boys were among 11 being treated at the Necker Hospital for Sick Children in Paris for X-SCID, a gene defect that blocks the development of a child鈥檚 immune system. One of the boys died, but when the other recovered to full health, the decision was taken to restart the trial (New 杏吧原创, 8 January, p 12).
鈥淭he gene therapy virus activated a gene that then triggered leukaemia鈥�
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The therapy was blamed for the earlier cases. Alain Fischer, head of the team at the Necker, takes bone marrow cells from the children and exposes them to a virus that inserts normal copies of the defective gene into the cells. When the cells are re-implanted, they allow the boys鈥� immune systems to develop normally. But in the case of the two who developed leukaemia, the virus activated the LM02 gene, which triggered the cancer. Fischer and his colleagues at the Necker are investigating whether the same thing happened in the new case.
Staff at Great Ormond Street Hospital for Children in London, who have used a similar regime to treat seven boys and one adult, say they have not had similar problems. 鈥淲e鈥檙e studying the reports from Paris carefully for any implications for our clinical trials,鈥� a spokesman says.
