A woman suffering from sickle cell disease (SCD) has been cured after her DNA was altered using the latest gene editing biotechnology. Sickle cell disease is a genetic condition that leads to normally circular red blood cells taking on a crescent shape. It also sees them become sticky and rigid. The inherited disease causes sufferers severe pain but patients that have benefitted from the new biotech treatment will now start 2020 free of the agonising symptoms.
The gene-editing trials, which have been conducted on patients in the USA and Germany, offer hope of a definitive cure for both SCD and beta thalassemia. Both conditions are genetic and mean blood struggles to perform its role of carrying oxygen around the body. Patients suffering from both conditions need to undergo regular blood transfusions – usually between 15 and 20 a year.
Recent developments in the biotechnology of gene editing, particularly the discovery of the cheap, high-precision Crispr-Cas- gene-editing tool, offers new hope for cures or treatments for a swathe of genetic diseases and conditions. British patients suffering from genetic blood diseases such as SCD and beta thalassemia could also benefit from the new therapies by as early as next year. While still considered experimental, having not yet passed through enough clinical trials to be considered confirmed as effective, results so far are proving highly promising.
One British SCD patient, 34-year-old Victoria Gray, has already had her DNA altered to stimulate her body to produce foetal haemoglobin. The substance is normally only produced by babies up until the age of around six months but has been shown to reverse SCD symptoms. Haydar Frangoul, Ms Gray’s doctor, commented:
“This approach is very exciting. If it is found to be safe and effective it can offer every patient with sickle cell disease a potential treatment.”
David Altshuler, chief scientific officer at Vertex, one of the companies behind the trials believes that early results demonstrate that new gene-editing techniques represent:
“a scientific and medical milestone — the rapid and responsible evolution of Crispr technology from discovery of a technique suitable for a lab to a possible therapy with the potential to help patients with sickle cell disease.”
Until now, the only known cure for SCD has been a bone marrow transplant. Not only is that a highly invasive and serious procedure but it also relies on a suitable donor being found and runs the risk of the transplant being rejected. That results in death.
The new gene-editing treatment is, however, also not a simple therapy. Bone marrow stem cell are taken from the patient and are then editing using the Crispr-Cas9 tool. In Ms Gray’s case, the tool attached itself to the DNA of her extracted bone marrow stem cells and disabled the gene that stops foetal haemoglobin from being produced after infancy. Billions of her bone marrow stem cells were treated this way. She then underwent a course of chemotherapy to kill her existing bone marrow before the edited cells were infused back into her body to regrow new, healthy bone marrow.
A similar process has been used to successfully treat a beta thalassemia patient. University College Cork’s Ciaran Lee commented on the still developing biotechnology:
“What remains to be seen is if the stem cells corrected by Crispr can survive for the lifetime of the patient, providing a permanent cure, or if the effect is temporary.”