Patients with the most severe form of the rare blood condition Wiskott-Aldrich Syndrome have now been free of the disease for four years.
Although the disorder affects fewer than one hundred children in Britain, the pioneering therapy offers hope to the hundreds thousands of people suffering from other genetic blood conditions such as sickle cell anaemia.
Daniel Wheeler, 15, of Bristol was among seven children who have been trialling the new gene therapy at centres in London and Paris.
Daniel was diagnosed with the condition aged two and had needed frequent medical care to manage his symptoms which included severe eczema, asthma and inability to fight infections. His older brother died from complications linked to the disease.
But since undergoing gene therapy in 2011 Daniel has shown no symptoms and doctors believe he is effectively cured.
Daniel’s mother Sarah, 50, a letting’s consultant from Bristol said: “Since being around two, Daniel has been in an out of hospital, but now his skin has cleared up and so has his asthma. It means he can get on with his life now.”
Adrian Thrasher, Professor in Paediatric Immunology, at Great Ormond Street Hospital in London, where the treatment was carried out, said that it offered new hope for people suffering from incurable disease.
“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,” he said.
“The work shows that this method is successful in patients who, in the past would have very little chance of survival without a well match bone marrow donor.
“It also excitingly demonstrates the potential for treatment of a large number of other diseases for which existing therapies are either unsatisfactory or unavailable.”
The treatment works by removing bone marrow stem cells – the type of cells which create new blood cells – and replacing the faulty part of the genetic code with a healthy gene. When the stem cells are replaced in the patient they then begin producing healthy blood cells, free from disease.
Seven children between the ages of eight months and 15 years were chosen because a bone marrow match could not be found. Without bone marrow transplantation, patients usually do not survive their teens.
All the children had eczema and associated recurrent infections and most experienced severe bleeding and autoimmune disease that, in one case, confined the child to a wheelchair.
The children went from spending an average of 25 days in hospital to no days in the hospital in the two years after the treatment. And the child using the wheelchair was able to walk again.
Fulvio Mavilio, Chief Scientific Officer at Genethon, the biotech company which developed the treatment said: “It is the first time that a gene therapy based on genetically modified stem cells is tested in an international clinical trial that shows a reproducible and robust therapeutic effect in different centres and different countries.”