The United States Food and Drug Administration (FDA) has approved a treatment for sickle cell disease.

The therapy, called Casgevy, from Vertex Pharmaceuticals and CRISPR Therapeutics, is the first medicine to be approved in the United States that uses the gene-editing tool CRISPR, which won its inventors the Nobel Prize in Chemistry in 2020.

The approval marks the first of two potential breakthroughs for the inherited blood disorder. The FDA on Friday also approved a second treatment for sickle cell disease, called Lyfgenia, a gene therapy from drugmaker Bluebird Bio.

Both treatments work by genetically modifying a patient’s own stem cells. Until now, the only known cure for sickle cell disease was a bone marrow transplant from a donor, which carries the ri§k of rejection by the immune system, in addition to the difficult process of finding a matching donor.