Result of this ongoing trial, which is the first to use CRISPR to treat inherited genetic disorders, were announced [June 12] at a virtual meeting of the European Hematology Association.
[Editor’s note: CRISPR gene editing was used to cure two patients – one with beta thalassaemia and one with sickle cell disease.]
“The preliminary results… demonstrate, in essence, a functional cure for patients with beta thalassaemia and sickle cell disease,” team member Haydar Frangoul at Sarah Cannon Research Institute in Nashville, Tennessee, said in a statement.
Beta thalassaemia and sickle cell disease are conditions caused by mutations that affect haemoglobin, the protein that carries oxygen in red blood cells.
In this trial, run by collaborating companies CRISPR Therapeutics and Vertex, bone marrow stem cells are removed from people and the gene that turns off fetal haemoglobin production is disabled with CRISPR.
The remaining bone marrow cells are killed by chemotherapy, then replaced by edited cells. This is done to ensure that new blood cells are produced by the edited stem cells.
Although the three patients did experience some adverse effects due to the chemotherapy, the CRISPR gene editing appears safe. However, the patients may need to be monitored for the rest of their lives to be sure it has no adverse effects, says [researcher Marina] Cavazzana.