Eric B.  Kmiec, PhD The recent approval by the U.S. Food and Drug Administration (FDA) of Casgevy, a therapy developed by Vertex Pharmaceuticals and CRISPR Therapeutics that uses CRISPR gene editing to treat patients with sickle cell disease, is a watershed moment in the history of this nascent field. I have been involved in gene therapy research for decades. Like many of my peers, I am thrilled that with this incredible breakthrough, CRISPR may be, as one story in GEN noted