The Food and Drug Administration said on Friday that it has some safety concerns about an experimental CRISPR-based treatment for sickle cell disease, citing the methods used by its makers to evaluate the risk of inadvertently making unwanted changes to patients’ DNA.
None of the concerns raised by the FDA on Friday, however, suggest the agency is reluctant to approve the treatment, called exa-cel, which is being developed by Vertex Pharmaceuticals and CRISPR Therapeutics.
Exa-cel, given as a one-time infusion, uses CRISPR genome-editing technology to patch up the genetic faults at the root of sickle cell disease.