In the news

Doctors at the Institute of Child Health (ICH) in London have reported the successful treatment of several children with severe combined immunodeficiency (SCID) using gene therapy. SCID is a rare X-linked genetic disorder that prevents immune system function, leaving children so vulnerable to life-threatening infections that they have to live in ‘bubbles’ to protect them from infection. The disorder can be treated effectively with a bone marrow or stem cell transplant, but this procedure relies on the availability of a suitable donor, and on the child being strong enough to undergo the transplant. The disease was therefore one of the earliest candidates for gene therapy approaches. A report to be published in the next edition of The Lancet details the treatment of four boys, although the researchers that a total of seven such boys have now received gene therapy for X-SCID (see press release). Functional copies of the defective gene were introduced via a leukaemia viral vector to stem cells from the patients’ own bone marrow, leading to the restoration of near-normal levels of immune function. Dr Bobby Gaspar, one of the UK researchers, said: "We hope this paves the way for developing gene therapies for other genetic disorders", citing the examples of other forms of inherited immunodeficiency or sickle cell anaemia.

Previously, concerns have been raised about this form of gene therapy when two out of eleven children treated for X-SCID with this form of gene therapy at the Necker Hospital in Paris developed identical forms of leukaemia (see journal club article). Commenting on this latest publication, Dr Marina Cavazzana-Calvo of the Necker Hospital said: "This paper is very important. It shows that this approach is highly reproducible…The safety issue is always a concern, but we hope that it will be limited" (see BBC news report). As yet there have been no further cases of leukaemia among children in the Paris or London gene therapy trials.