06 March 2017
ByAppeared in BioNews 891
A teenage boy in France appears to have been cured of sickle cell disease using a gene therapy. He has been free of all signs of the disease for 15 months.
Gene therapy has successfully treated some rare genetic disorders, but this is the first time it has worked on a common genetic disease.
'The patient is now 15 years old and free of all previous medication,' Dr Marina Cavazzana of the Necker Children’s Hospital in Paris told New Scientist. 'He has been free of pain from blood vessel blockages, and has given up taking opioid painkillers. All the tests we performed on his blood show that he’s been cured, but more certainty can only come from long-term follow-up.'
Sickle cell disease is caused by a mutation in the gene that makes beta-globin, part of the haemoglobin molecule. This change causes red blood cells to develop into an abnormal sickle shape, which causes clumping and blood-vessel blockages. This leads to pain and organ damage and can be fatal if untreated.
The boy had been suffering from repeated episodes of severe pain and had to receive blood transfusions once a month to manage his symptoms. When he was 13, he began the experimental treatment.
Doctors removed some stem cells from his bone marrow and used a virus to deliver mutated versions of the beta-globin gene designed to interfere with the boy's defective proteins. Three months after treatment began, he began producing normal haemoglobin and has been symptom-free since then. The case study was published in the New England Journal of Medicine.
'I've worked in gene therapy for a long time and we make small steps and know there's years more work. But here you have someone who has received gene therapy and has complete clinical remission – that's a huge step forward,' she told BBC News.
Dr Cazanna says that she and her team are treating seven other patients, who are showing 'promising' progress.
Sickle cell disease (SCD) affects millions of people worldwide, most of them in sub-Saharan Africa. As much as two percent of babies in Nigeria are born with the disease.
'We should be realistic in remembering that there are hundreds of thousands of sickle cell patients in less developed countries, and that the therapy is not easily exportable or adaptable to countries with less well-developed health systems,' cautioned Professor Stuart Orkin of Harvard Medical School.