EU approves first gene editing therapy

The European Medicines Agency, the EU drug watchdog, has approved the first medicine using CRISPR/Cas9, a novel gene-editing technology. Casgevy (exagamglogene autotemcel) is indicated for the treatment of transfusion‑dependent beta thalassemia and severe sickle cell disease in patients 12 years of age and older for whom haematopoietic stem cell transplantation is appropriate and a suitable donor is not available.

This new therapy may free patients from the burden of frequent transfusions and painful vaso-occlusive crises that occur when sickled red blood cells block small blood vessels, and has the potential to significantly improve their quality of life.

Beta thalassemia and sickle cell disease (SCD) are two inherited rare diseases caused by genetic mutations that affect the production or function of haemoglobin, the protein found in red blood cells that carries oxygen around the body. Both diseases are life-long debilitating and life-threatening.

Casgevy is a cell-based gene therapy medicinal product using CRISPR/Cas9 technology to edit the patient’s own blood stem cells. It is a personalised one-off treatment that involves mobilising bone marrow stem cells from a patient’s blood.

CRISPR gene-editing finds a specific sequence of DNA inside a cell. Using ‘molecular scissors’ to make precise cuts, it enables adding, removing or altering genetic material at that specific location of the genome of the cells. With Casgevy, stem cells are edited at the erythroid-specific enhancer region of the BCL11A gene which usually prevents the production of foetal haemoglobin (HbF). These modified cells are then infused back into the patient, and the reduction of BCL11A gene transcription leads to increase of HbF production thus providing functioning haemoglobin.

Casgevy was supported through EMA’s PRIority MEdicines (PRIME) scheme, which provides early and enhanced scientific and regulatory support to medicines that have a particular potential to address patients’ unmet medical needs.