Sickle cell disease (β-thalassemia) gene therapy starts both in Europe and the US

CTX001, gene therapy trying to ease the symptoms of β-thalassemia, was approved to start for the first time in the UK, Germany and the United States.

CTX001 aims to use CRISPR technology for editing progenitors of red blood cells (hematopoietic stem tissue). The cells are extracted from a patient’s body and modified by change of a sequence near the gene BCL11A. Edited cells are then inserted into the body.

Correction of an enhancer sequence (a region enhancing activity of a gene) leads to higher activity of the BCL11A, resulting in a raise of fetal hemoglobin molecules in red blood cells. A higher level of fetal hemoglobin was found to be lowering mortality and easing of the symptoms of sickle cell disease (type β-thalassemia). The gene therapy tries to exploit this effect.

The primary goal of CTX001 is transfusion reduction. The trials will be going to 2021 and will involve several dozen patients.