A preliminary safety study has shown that gene therapy may be able to help sufferers of haemophilia. The study, results of which were published in the New England Journal of Medicine last week, involved six people with severe haemophilia A, a disorder caused by the failure of a gene called factor VIII which codes for a protein necessary for blood clotting.
The researchers, from the Beth Israel Deaconess Medical Centre in Boston, USA, modified cells taken from skin on the patients' upper arms by adding the Factor VIII gene taken from healthy humans, and grew them in a laboratory. Between 100 million and 400 million cells were then reimplanted into each of the patients.
After four months, four of the patients had higher levels of the gene in their blood than before the treatment, but not enough for them to forgo their usual treatment which involves intravenous infusions of the protein. No factor VIII was detected in any of the patients after ten months. The researchers do not know whether the implanted cells died or just ceased to function.
The study undertaken used only a small number of patients, but Dr David Roth of the Boston Centre is encouraged by the results. He said that the findings suggest that 'gene therapy has a major potential to transform the way we care for patients with haemophilia'. Other scientists remain unconvinced both by the temporary nature of the results and the disparity among the outcomes in the patients. Dr Inder Verma from the Salk Institute in San Diego noted that two of the patients did not respond to the treatment and that implanting more cells did not alter this.