The US Food and Drug Administration (FDA) will review the biologics license applications (BLA) for exagamglogene autotemcel (exa-cel) as a gene-editing therapy for sickle cell disease (SCD) and transfusion-dependent beta-thalassemia, according to Vertex Pharmaceuticals and CRISPR Therapeutics.

“Exa-cel could be the first CRISPR gene-editing therapy to be approved by the FDA”, Vertex CEO and president Reshma Kewalramani stated.

In April, these two companies submitted BLAs for the use of their experimental drug in severe SCD and transfusion-dependent beta-thalassemia. The FDA is expected to review the use of exa-cel in SCD treatment until December 8, and in transfusion-dependent beta-thalassemia treatment until March 30, 2024.

The companies have also submitted to the FDA the interim data from pivotal trials. According to these studies, 16 of 17 patients with SCD who received exa-cel remained free from severe vaso-occlusive crises for at least 12 months after treatment, and 24 of 27 patients with transfusion-dependent beta-thalassemia stayed transfusion-free for at least 12 months after treatment.

Read more about SCD experimental therapies

The detailed results from these trials were presented during the European Hematology Association (EHA) Hybrid Congress 2023, held in Frankfurt, Germany, this June.

The European Medicines Agency and the UK Medicines and Healthcare Products Regulatory Agency validated the Vertex and CRISPR Therapeutics’ marketing authorization application for exa-cel in January. These European agencies may make a regulatory decision on the investigational drug this year.

Exa-cel uses CRISPR-Cas9 to edit patients’ CD34-positive hematopoietic stem and progenitor cells ex vivo by modifying the BCL11A gene to achieve high levels of fetal hemoglobin in red blood cells after infusion back into the body. Patients with SCD and transfusion-dependent beta-thalassemia produce a dysfunctional protein that constitutes fetal hemoglobin.


FDA to review Vertex Pharmaceuticals, CRISPR Therapeutics’ SCD, beta-thalassemia gene-editing drug. News release. Vertex Pharmaceuticals and CRISPR Therapeutics; June 12, 2023.