Six boys with the inherited immune disorder Wiskott-Aldrich Syndrome (WAS) have
been successfully treated with a gene-therapy technique that harnesses a 'tamed'
The six-year trial was held at Great Ormond Street Hospital in London, and Necker Children's Hospital in France. In six out of seven boys, the therapy successfully reversed symptoms such as eczema, recurrent infections and bleeding. One French child with a severe form of the disease no longer needs a wheelchair.
Wiskott-Aldrich Syndrome is a serious immune-deficiency disorder that affects around one in 250,000 males. It results from a defective gene called WASP, which is found on the X chromosome. Previously, the only cure was a bone marrow transplant from a matched donor. But the recent study, published in the Journal of the American Medical Association, used a modified HIV virus to 'infect' the boys' bone marrow stem cells with a healthy version of the WASP gene. When these were returned to the patients, they began producing healthy blood cells.
Adrian Thrasher, professor of paediatric immunology at Great Ormond Street Hospital, and the study's author said: 'If the positive effects of the treatment can be maintained even further in the future, it will provide confirmation that gene therapy can provide a "cure" for this life-limiting condition and for many other similar bone marrow disorders.' He told the BBC, 'We are entering a new era where genetic treatments are entering mainstream medicine and offering hope to patients for whom conventional treatments don't work well or are simply unavailable.'
Earlier forms of gene therapy had unintended consequences, as the inserted genes indiscriminately switched on other genes, including cancer genes, causing several patients to develop leukaemia. Dr Emma Morris, an immunologist at University College London who is currently leading a gene therapy trial for leukaemia, told The Guardian: 'People have been working on [gene therapy] for ten years and it's now becoming a reality that you can safely genetically modify cells and introduce them into people.'
Daniel Wheeler, 15, of Bristol, is one of those who benefited from the treatment. After enrolling on the trial in 2011, Daniel spent five weeks in isolation being treated and was able to go back to school seven weeks later. 'My life has completely changed since having gene therapy. My skin is eczema free and I have a lot less joint pain. It means I can focus on my GCSEs at school without worrying about so many trips to hospital,' he said.
Although the study has demonstrated the feasibility of this type of gene therapy, Professor Thrasher acknowledges that controlled trials with more patients will be needed to assess long-term outcomes. His team are now hoping to start new trials for patients with sickle cell disease and thalassaemia, which are among the most common inherited genetic disorders in Britain.